PHP 8 no longer silently ignores fatal errors. Background processing of profile pictures in our self-hosted instance was failing on system\Images\Gd.php line 224, which throws a fatal error on imagecolorsforindex if the computed transparency index of a GIF is outside the color range of the image. Fortunately, someone else document a fix at https://github.com/processwire/processwire-issues/issues/1299, which worked (after substituting variable names):

// Suggested by https://github.com/processwire/processwire-issues/issues/1299
 $transcol = $transindex != -1 ? @imagecolorsforindex($this->image, ($transindex < imagecolorstotal($this->image) ? $transindex : $transindex - 1)) : 0;
//                                      $transcol       = @imagecolorsforindex( $this->image, $transindex );

 

Edited August 31, 20222 yr by Rodrigo Castillo

Thank you for bringing this issue to our attention! I can confirm this should be further reviewed and I have logged an internal bug report for our development team to investigate and address as necessary, in a future maintenance release.

 

This apply the patch showing in the support area of your admin CP. This should resolve the issue you are having.