I am looking for a loss-less JPEG optimization tool that I can include in a PHP-based photo gallery software.
I already checked the following question, but ruled out the tools mentioned there for reasons I'll explain below:
The command line tools jpegtran and jpegoptim are not available in the average PHP hosting account. The web-based tools (www.smush.it, www.kraken.io) all have a limit of 1 MB for processed images.
The 1 MB limit is a problem, because the gallery software delivers images based on browser-size and I also want to support Full HD and even larger displays. Depending on content, photos prepared for such resolutions can get larger than 1 MB.
Any hints on a solution are appreciated!
There are no solution.
Either use some command-line utility or increase memory limit.
(and, to let you know, it's not target image file size but uploaded image dimensions that puts you into trouble with memory limit.
OK, I found my answer in another stack overflow question:
JPG File Size Optimization - PHP, ImageMagick, & Google's Page Speed
ImageMagick already does the Huffman optimization. I assumed it doesn't because my ImageMagick files were still larger then the ones from jpegtran & Co. However, that was only because I did not strip the metadata.
Cheers, Robert