I just performed an upgrade from 7.3.1 to 7.5.2. The upgrade went reasonably smoothly, most of my trouble was needing to tweak CSS styles until my boards were readable again. The only things not working (that I've discovered so far) are trouble with images.
When attempting to upload to a Gallery, I get this error message:
Fatal error: Call to undefined function: resize_image_() in /path/to/my/forum/libs/image.inc.php on line 66
Anticipating questions, yes, permissions are correct on all relevant directories and files, yes I made certain I have file upload size set to 2M
in php.ini, yes I was uploading small sample files of less than 100kb each just to test the gallery, yes I made certain the uploading permissions were set properly in the Control Panel. Gallery uploads were working prior to the upgrade.
Other image-related problem: inline display of regular small attached image files as images is not working, I'm just seeing text links for attached files. This was also working correctly before the upgrade.
I'm at wit's end; can someone please help me out?