In D551#11308, @erik wrote:

\ImageHelper::ResizeImage - change "thumb_format" of poll's "Image" field to "resize:200x200;default:core/admin_templates/img/ajax_iframe_progress.gif" and try uploading a large (>200 by width/height) file on the poll editing page in the Admin Console

convertPathToRelative is called to convert each element in the $params array, however only "default" parameter contains file path. There are made excessive convertPathToRelative calls for some parameters (quality, output_format, etc.)

\ImageHelper::ResizeImage - change "thumb_format" of poll's "Image" field to "resize:200x200;default:core/admin_templates/img/ajax_iframe_progress.gif" and try uploading a large (>200 by width/height) file on the poll editing page in the Admin Console

After clean install
Part 4.9 - confirm that you'll see an error message above the system settings list indicating which folders weren't deleted as part of the system setting change. - There appears only "Please manually delete paths:" message. No folder names are present in the message.

Restored chages in the TemplatesCache class, that were accidentally removed.

Corrected permissions on the system folder itself. Report indirect compiled template removal as part of system setting change.