Is there any way , so that the users to be able to upload big pictures, but on server to be resize on some demensions ,and if needed to get lower quality so to fit some filesize limit?
Thanks!
Yes.
You could approximate it using 'Auto resize images that are larger than max width or height' and disable bitmaps.
Disable the file extension "bmp", that is. Other image file extensions (jpeg, gif, tif) are bitmaps as well.