Hi Tim,
Number of image pages are only logged when you directly delete pages in Document Viewer. When an entry is deleted, events 'Delete Entry', 'Recycle Entry' or 'Purge Entry' will be logged. Pages deleted along with the deletion of this entry will not be logged.
Yet there's a way to know a deleted entry's page count. For each entry that's deleted, if there were image pages belonged to it, a 'Create Page' event would be logged for each page of the entry. In Audit Trail Report, please select events 'Delete Entry', 'Recycle Entry', 'Purge Entry' and 'Create Page', then sort by column Entry ID. If a Create Page event and one of the Entry Deletion events both exist for the same Entry ID, this entry contained image pages before was deleted. The maximum number in 'Page number' column for a 'Create Page' event for this entry would indicate total pages it contained.
For massive amount of entries deleted, easiest way to see would be to download this report from Audit Trail. Sample attached, where Recycle Entry event with Entry ID 7638 had 4 pages before entry was deleted.
Thanks!