Utility to re-compress images?

[J.R. Rogers]

PhotoPost PHP allows you to set a dimension limitation on photos to display (triggering a shrink of images uploaded that are larger than the specified size), but there's only an image size (kb) limitation on the upload. If my gallery is configured to allow pictures up to 800x800 and I allow an upload size of 1MB, someone can easily upload a 1MB "uncompressed" jpeg which is now showing up in the gallery when someone clicks "large image".

Is there any way to have PhotoPost automatically re-compress images that are uploaded larger than a set threshold of say 100k? If not, is there a utility that allows me to parse through my images directory and re-compress images?

Thanks,
JR

[Chuck S]

I do not know of such a utility offhand

ImageMagick is performing its duty quite well

I can take 2 pictures of the same photo one being 700k uncompressed and one 125k compressed and ImageMagick will upon resize then compress them. The pictures can be identical. ImageMagick has no control over that aspect. It will only resize them if over the thresholds

If both images are 700x500 and your thresholds are higher like you stated then obviously the higher KB image will not be allowed because of your file upload limit

You need to tweak your settings for the optimum for your situation.

[J.R. Rogers]

Originally Posted by omegatron

If both images are 700x500 and your thresholds are higher like you stated then obviously the higher KB image will not be allowed because of your file upload limit

You need to tweak your settings for the optimum for your situation.

Thanks for your reply, Omegatron. In keeping the board easy to operate for my user base, I set a high threshold on the upload. Most of my users are doing good to be able to get the images off of their digital cameras, much less shrink them to below a certain threshold before uploading. I'd prefer to leverage the technology and allow it to adjust images according to parameters that I establish. Setting a dimension limit that triggers a recompress is an awesome feature. But you can have an 800x600 JPEG that is 800k+ in size. It's already happened on my board, and that's a terrible waste of bandwidth. The only way I know of to fix it is to ftp the file to my system, recompress it, and FTP it back. Why do that, when the technology already exists on the server with GD2 and ImageMagick?

It sounds like the settings that I need to tweak are not available. IMO there should be an image size limit that is separate from the upload limit, that will trigger a re-compress, just like there's a dimension limit that will trigger a shrink/re-compress.

JR

[Chuck S]

You miss what I am saying

The medium threshold triggers a recompress based on image dimension. The width and height thresholds trigger a recompress based on the same. If your thresholds are high and the image is lower than your set thresholds then the image is basically just copied since ImageMagick does not really touch it. Thus as I explained above.

[J.R. Rogers]

Originally Posted by omegatron

You miss what I am saying

The medium threshold triggers a recompress based on image dimension. The width and height thresholds trigger a recompress based on the same. If your thresholds are high and the image is lower than your set thresholds then the image is basically just copied since ImageMagick does not really touch it. Thus as I explained above.

Thanks, Chuck. I think I understand what you're saying. You're right - if the image is lower than your dimension thresholds, then the image will simply be copied. The software doesn't care how big the image is in KB, and that's my point.

For example:
If my maximum dimensions were set at 600x600
Someone uploads a JPG picture that is 600x600 and 650kb in size
the medium dimension limit is set at 400 so a medium images is created
The full size and compressed medium images are copied.
Now I'm transmitting a 60kb medium file and a 650kb full size file, Every user that clicks on the picture is sucking up 710k of bandwidth. That's the problem.

The 650kb image doesn't need to be 650kb. It can probably be re-compressed to 100k or less without dramatically affecting the image quality, and not changing the size from 600x600. But there's no image size (kb) threshold to trigger a recompress. Even with relatively low dimension thresholds, someone can still upload a big honkin' file that's been download hundreds of times before I even notice.

I can either prevent users from uploading those images (with the kb upload limit), or I can live with people sucking up a ton of bandwidth. That doesn't make sense because GD2 and ImageMagick can both recompress the images without resizing them. In this scenario, the bandwidth difference would be 710k versus 160k.

JR