annedi

Thanks, Marc.

Happy that resizing only affects new images. That's what we need. What is the benefit from rebuilding System Cache? Is that something which I should be doing occasionally?

QUESTION 1 Regarding: System > Settings > Posting > General > Images & Videos > Maximum Image dimensions to save If I set maximum dimensions for uploaded images, then it is shown that: If an image larger than these dimensions is uploaded, it will be resized to no bigger than the dimensions and the original image will be discarded. My question is whether setting max image dimension affects images uploaded prior to my setting this restriction? Ideally I would like to apply image dimension restrictions only going forward so that old uploaded images would not be affected. QUESTION 2 Regarding: Admin > Dashboard > Support > Tools & Diagnostics > Clear System Caches What does "clearing system caches" actually do? Are images included in "system caches"? THANKS in advance -- 🙂 Andrea B.

ok. I'm looking at this PHP image function reference. Perhaps it would be useful to someone else who has a photography website. https://www.geeksforgeeks.org/php-image-processing-and-gd-functions-complete-reference/

If you need less compression to happen, you can change this in your Admin CP > Files > Image Settings > JPG and WebP Quality. I already did that !! As reported above I have JPG quality = 100. I'll retry with ImageMagick. Currently it is not working, so it might need reinstallation with appropriate flags. 1) So nobody knows what PHP/Image function changes the quality? 2) Can the "Image library", GD, or ImageMagick be bypassed? (....probably not, but I'm curious anyway)

I found the files. Gd.php, Image.php.

Does GD resample the upload? Is there someplace I see what happens in the code?

Understood. 😀

I would think that uploaded files of any type shouldn't change just from uploading? We often upload non-JPG files to share (via downloads) and they never change. Like PDFs or raw photo files like NEFs, TIFFs, ARWs and so forth. We detected the differences between the original JPG and the website JPG by layering the two files in Photoshop and setting the top layer to Difference. The Diff frame was pushed a bit using Auto-Contrast because the JPG changes can be subtle if the original JPG was saved with high quality. Here is one example showing typical JPG compression changes around edges. I was testing here with a very large ((too large)), high quality file. I'll try to get another more reasonable upload change and post that later. These JPG changes are not of earth shaking importance, but being a photography website we really would like to know what is happening or how to prevent it.

As mentioned, I do not have any restrictions set on image size for either saving or display.

My website is a photography website. So photo quality is important to us, but naturally there are constraints on what can be achieved. We do ask users to resize their images prior to uploading, but I do not have any restrictions on image size for save or for display set. (We are a very small forum, so if a members forgets to resize an image we ask them to fix that or we resize it for them.) I recently tested changes to uploaded JPG files. We are using GD with JPG and WebP Quality = 100. Any uploaded JPG file is altered as compared to the original JPG. The quality of the image is slightly decreased. Why is that? I had thought that setting JPG Quality = 100 would prevent such changes?

OK, I think it has all come together now. I'll summarize so that a solution can be declared. My website began to have sporadic image JPG upload failures. I couldn't completely correlate upload failures with image dimensions or file size, although upload failure did affect mostly large dimension JPGs. We had no problem with PNG uploads of any size. We had been using ImageMagick all along. Lowering the ImageMagick quality setting did not fix the problem. Marc suggested switching to GD. That stopped the JPG upload failures. Thinking back, I realized that the upload failures began after the change to PHP 8.1.21. Randy suggested that the host might have missed setting some flag/option to ensure ImageMagick ran properly with PHP 8.1.21. So, as Marc suggested, I will ask my host to fix this PHP/ImageMagick incompatibility. Thanks to SeNior-, Randy, Jim M and Marc for their useful suggestions and help. 😃

My error: Our host server is running PHP 8.2.8. The forum software, however, is using PHP 8.1.21. I went to look up PHP versions and cited the wrong one above. Pls excuse me! (It was late.) Anyway, ImageMagick is having problems under PHP 8.1.21 for our website. The switch to GD seems to be working. Shouldn't they both be usable with 8.1.21?

Switching to GD seems to cure the problem. Whew....I really really hope that turns out to be true. But I need to run with GD for a couple of days to be sure. Why in the world would ImageMagick "suddenly" start causing problems? Could it have anything to do with upgrading to PHP 8.2.8?

Switching to GD seems to cure the problem. Whew....I really really hope that turns out to be true. But I need to run with GD for a couple of days to be sure. Why in the world would ImageMagick "suddenly" start causing problems? Could it have anything to do with upgrading to PHP 8.whatever?