Thank you for replying, on a PHP newsgroup someone guessed a little and said I should try using imagecopyresampled instead of imagecopyresized. At least the overall quality of the pictures is better. I have yet to see the pixelated bug happening again with this new function. I'd guess the bug has to do with the type of the JPG, I know it's a strange format, can be different either it's from mac or pc, or with or without embedded colour palette, etc. It is not a case of the original image being too small and thus generating big blocks at a reasonnable size, it's not about compression either, they are pixel-type block, not compression like blocks. At least it works better now, imagecopyresampled is better, but you should check the version of GD library is old enough to allow it. Cheers, Damien COLA -----Original Message----- Maybe the image that is uploaded was compressed to much to begin with, and saving the server side image in various size, and recompression just cuases way to much data loss, and the image turns out crappy. On small thumbnail images, you won't see the difference to much, but larger ones you will.