Posting images^

[grazie]

MikeB has written an excellent guide to posting links and images in the Almanac. I like to view high resolution pictues as much as anyone ('say no more...'), but posts that contain lots of links to full size images can make the user experience a little tedious, even with high speed connections. Once the images are quoted within the thread it starts getting a bit messy. It's standard practice to use smaller images or thumbnails on websites, yet I can't remember seeing it done on this forum. So if I wanted to post a set of eight high res photos, I'd create a set of thumbnails, post those and make each thumbnail link to the fullsize image as follows.





This is achieved by nesting the IMG tag within the URL tag.

Code: Select all

[url=<full size image>][img]<thumbnail image>[/img][/url]

In the above example each thumbnail is

Code: Select all

[url=http://www.gla.ac.uk/medicalgenetics/2006/060107DSC01026.jpg][img]http://www.gla.ac.uk/medicalgenetics/2006/060107DSC01026_small.jpg[/img][/url]

Even for just one photo, it can make the thread much cleaner. The photo is one taken in Cuan Sound by Douglas Wilcox. It was used for illustration in the Almanac, so I'm hoping he doesn't mind me using it again here.

[Steve B]

People do sometimes post overly large images and it can be a pain. Most of the time the best answer is simply to keep the size of the posted image down to say 600 pixels wide. That's easily big enough for most purposes. Also, avoid very high quality JPEG settings, a medium quality JPEG is usually good enough and will download much faster.

This one is 600px wide and is only 34k - at that size it's hardly worth the bother of making thumbnails. (Sorry it's not sea kayaking, it's just one I happened to have available online.)


But when you want to post a large number of images the thumbnail idea is great.

[adrian j pullin]

Give us a clue, Steve B. Where is it?

[Jim]

Hmm, I never post hi -res images, but do tend to post 800x600 ish images because they will fill most people's browsers.
I prefer to view the image inline rather than have to load a separate page for it via a thumbnail link, therefore I put my images inline....
The last few may not have been very well compressed though - I forgot to change the compression options after scanning a load of genuine hi-res stuff. I may recompress the offending images tonight, if I remember.

Totally agree about quoting pictures though, it's unnecessary, but since it should refer to the same picture in memory shouldn't make things slower, just messier.

Jim

[JMT]

Give us a clue, Steve B. Where is it?

Embrum?

[Steve B]

Hmm, I ... tend to post 800x600 ish images because they will fill most people's browsers.

I'd have no objection to 800 if you think the photograph justifies it. Just remember that 800 wide is 1.33^2 bigger - over 75%, which translates fairly closely to a 75% bigger download.

For panoramic seascapes you might want to go even wider, I can understand that.

[Steve B]

Give us a clue, Steve B. Where is it?

As Mike said, it's the play wave at Embrun. It's a great spot - next time you're in the Alps be a bit more careful with your shoulders and you might get to see it for yourself ;-)

[andreadawn]

So what sort of maximum file size is appropriate? The guide in the almanac only mentions image dimensions.

I resize mine in photoshop, usually to 600 pixels wide at 72dpi giving files of about 250kb which is presumably too big. I have tended to use the high quality jpeg settings. Reducing the quality to medium gives a file of about 70-90kb.



Better? Or still too big?

Andrea.

[Mark R]

I stick to 600 pixels wide as a maximum.

[grazie]

So what sort of maximum file size is appropriate?

I think 50K maximum is often used as good guide for image sizes on a webpage. A couple of images over this size will not make a lot of difference.

The trouble with using images that are 800 wide is that the forum table width has to increase to accommodate them, which then requires horizontal scroll to read the thread for most users. This can be a pain!

Edit: changed vertical to horizontal in the last paragraph.

[Steve B]

Regarding file sizes...

We've already touched on the fact that images can be less compressed to retain quality, or more compressed to make the files smaller at the expense of quality. Another factor which comes into play is that some images are inherently easier to compress - open seascapes often contain relatively little detail and result in smaller files than busy, detailed landscapes for example. This is not a settings issue - compress both on "medium" and the seascape will result in a smaller file. There's nothing to be done about this, it just means that files sizes will vary and there is no size which is right in every case.

One important point, especially if you are using Photoshop to process digital camera images (as opposed to scans) is that JPEG files can contain information over and above the image itself which takes up more space. This is includes 'EXIF' data which is stuff like what camera was used, shutter speed and aperture, date and time and much more. That can easily run to a few kB of extraneous data. It may also include a 'colour profile', which tells colour management systems how to reproduce the image accurately - another few tens of kB. And it can contain an embedded thumbnail - another few kB. It's not unusual for a 70kB JPEG to have 35kB of image and 35kB of unwanted baggage - all of which can be discarded. Photoshop makes this very easy. Just make sure you choose "Save for Web" and not "Save As" when saving your 600px wide image. That automatically strips out this unwanted stuff. It also has a slightly different compression algorithm which is designed to work well for low resolution images.

[Steve B]

Hmm, I ... tend to post 800x600 ish images because they will fill most people's browsers.

I'd have no objection to 800 if you think the photograph justifies it. Just remember that 800 wide is 1.33^2 bigger - over 75%, which translates fairly closely to a 75% bigger download.

For panoramic seascapes you might want to go even wider, I can understand that.

Just to clarify, following Mark's and Grazie's posts - I still stick to the 600px recommendation that I mentioned originally, I'm just saying that wider is ok if there is a good reason. But 600px wide is ideal.

[MikeB]

Just updated the image-posting article - thanks all - Mike

[Steve B]

Just noticed something as I was doing an unrelated job. The medium quality JPEG setting in Photoshop's Save for Web is actually called "JPEG High". Also, there's a big jump from "JPEG Medium", which is 30 on the numeric scale on the right, to "JPEG High" which is 60. Intermediate settings can be quite useful, such as if you have an image which is basically ok on JPEG Medium but perhaps shows a few distracting artefacts in smooth areas of sky - common problem. Just nudge the number up a little until you're happy with it, remembering that you are not seeking perfection.

All this relates to the full version of Photoshop. I don't know the specific details for Photoshop Elements, which many people are probably using - but the principle is the same.

[andreadawn]

OK thanks for that Steve. That's very helpful.

I wasn't using the Save for Web feature. Will do in future. I've posted quite a lot of largish images in the past including a lot on one thread but nobody said there was a problem.

Photoshop Elements seems to be pretty much the same where the Save for Web stuff is concerned.

Andrea.

[Steve B]

In general I don't think there is a problem, but even with broadband it's nice when pages load a bit faster.

When discussions turn to photography per se, rather than the stuff in the photographs, I'll be sure to come back and tell everyone that they should leave the EXIF data in their images. It can be very useful - and it's only a few kB ;-)

[Jim]

The trouble with using images that are 800 wide is that the forum table width has to increase to accommodate them, which then requires vertical scroll to read the thread for most users. This can be a pain!

Rubbish, I view much bigger at home using a screen resolution of 1280x1024 and at work I use 1600 x 1200 because of the amount of CAD I do - as far as I'm concerned 800 pixels wide should cater for anyone using 1024x768, any lower resolution that that and you computer is even more prehistoric than mine and should be replaced without a second thought. Mine will be if I ever have enough money to get round to it.

Anyway, 600 or 800, I'm still guilty of barely compressing the last few, time to fire up PSP and sort that out!

Jim

[Jim]

OK, so the image in question (I suspect mine sparked the thread) is still 800 high by 519 wide but just by saving with the compression slider set half way (50) it has dropped to 29kB. Does anyone have a problem with that? It's smaller than steves 600x480ish example above....

Stupidly I forgot to note the orignal web file size, a couple of hundred I think, the 1200dpi scan I made it from is over 1MB - I would never stickl one of them inline!

I also sorted out the images in the canoeing area, some of which I haven't actually linked yet - Doh!

Jim

[Martin S]

When discussions turn to photography per se, rather than the stuff in the photographs, I'll be sure to come back and tell everyone that they should leave the EXIF data in their images. It can be very useful - and it's only a few kB ;-)

Steve I don't know what browser you use but if its FireFox there is an extension that lets you read the Exif info of an image, just by right clicking. Check out http://ted.mielczarek.org/code/mozilla/fxif/

Martin

[Jim]

I've gone right off firefox. Version 2 seemed to have brought my PC to it's knees yet scanning slides seemed to be at the same speed so I'm experimenting with IE (spit) again and finding it loads faster.

When are mozilla going to sort out the gecko engine? They have a great browser with a monumental flaw!

Jim

[Martin S]

I've gone right off firefox. Version 2 seemed to have brought my PC to it's knees yet scanning slides seemed to be at the same speed so I'm experimenting with IE (spit) again and finding it loads faster.

When are mozilla going to sort out the gecko engine? They have a great browser with a monumental flaw!

Jim

I am happy with FF2 no speed issues here. AND it doesn't have some of the none compliant quirks that IE has.....

Martin

[Steve B]

Steve I don't know what browser you use but if its FireFox there is an extension that lets you read the Exif info of an image, just by right clicking. Check out http://ted.mielczarek.org/code/mozilla/fxif/

Yep, I'm already using it. It's not very good, it has a strange bug that causes it to give a spurious sensor size (so can I trust anything else?), and the data is nowhere near as complete as IExif, which fulfils the same role in IE but is frankly in a different league.

[Steve B]

OK, so the image in question (I suspect mine sparked the thread) is still 800 high by 519 wide but just by saving with the compression slider set half way (50) it has dropped to 29kB. Does anyone have a problem with that? It's smaller than steves 600x480ish example above....

I don't imagine for one second that people will spend ages optimising images before posting them - nor is there any need to. But I've seen stuff posted here which is several hundred kB and that is a bit antisocial. I even found a 150 kB avatar once!

[Geoff Seddon]

Well that's me feeling guilty then, on all points, probably.

[Steve B]

Steve I don't know what browser you use but if its FireFox there is an extension that lets you read the Exif info of an image, just by right clicking. Check out http://ted.mielczarek.org/code/mozilla/fxif/

Yep, I'm already using it. It's not very good, it has a strange bug that causes it to give a spurious sensor size (so can I trust anything else?), and the data is nowhere near as complete as IExif, which fulfils the same role in IE but is frankly in a different league.

Update - IExif is now also available for Firefox - http://www.opanda.com/en/iexif/iexif_firefox.htm

[GrahamKing]

This old thread just seems a suitable place to file a recipe for posting images hosted on picasa. If you've been thwarted by the message "It was not possible to determine the dimensions of the image" here's a workround I discovered this afternoon:

In your web browser, display the photo at picasaweb.com. To the right of the image, click on "Link to this photo >". Choose the appropriate size from the drop-down list that appears, then select and copy the contents of the box entitled "Embed image".

Back at your UKRGB post, click on Img. Paste the contents of the clipboard between the [img]and[/img] tags that just appeared. You should now have something that looks similar to this:

[img]<table%20style="width:auto;"><tr><td><a%20href="https://picasaweb.google.com/lh/photo/f ... %20src="[b]http://lh5.googleusercontent.com/foo/fo ... width="640"[/b]%20/></a></td></tr><tr><td%20style="font-family:arial,sans-serif;%20font-size:11px;%20text-align:right">From%20<a%20href="http://picasaweb.google.com/sitename/pi ... </table>[b][/img][/b]

Delete everything except the stuff in red. Click Preview and check that your photo displays.

Mike, if this is helpful, it might be worth adding to the almanac article.

[MikeB]

Useful - thanks Graham - I've amended the article.