I need to change the image sizes in "Item image options" (xsmall, small, medium, large, xlarge)

I've searched a lot, but it seems that there are no way to do that, except from uploading all the images again. That is an option I rather not would do, because of the amount of images on my site.

Is there any way to do that, any free plugins or another way to do that, except uploading every image again?

Sincerely,
Martin

I'm afraid not. You can set the new dimensions for all your new items, maybe even upload some of the old ones again, and your old ones would just be resized to the new dimensions by html resize.

Yes you can with this php file

Where is the php file?