image optimizer for web

Older versions of Ping left the original modification date of the file. This was handy when the files are sorted by date. Newer versions of the program don't do that anymore. Would love to have an option to enable this feature.

If I could chime in, I find the modification date behavior of pingo (cmd-line) to be strange. If I ask it to optimize a directory of PNGs, it will change the modification date on everything, regardless of whether or not it was able to reduce the file size. For WebP, it will change the modification date if it is either able to reduce or MEET the original file size.

Since I tend to use the modification date as a tool to determine which files in a large directory of images have actually changed, it would be very helpful if the modification date were changed ONLY if pingo actually rewrote the file for all file types. And, except for cases where pingo tries to fix file corruption (if this is something it can do), it shouldn't be rewriting files unless it can reduce their size.