Really? I'm the only one having this problem?  Sucks to be me. 

Well the problem hasn't magically solved itself, but I've found some interesting ways to NOT fix the problem. 

-Renaming the file doesn't work. 
-Creating a new file in photoshop and copy/pasting the image into the new file under a new name doesn't work.

-Switching to the old (single photo) upload form doesn't work, but does produce this error message. 
Fatal error: Allowed memory size of 94371840 bytes exhausted (tried to allocate 3984 bytes) in /home/mercyphotos/cantonmercyphotos/admin/include/functions_upload.inc.php on line 549

So my follow up question is does piwigo allow photos in any format besides .jpg?  because my next step is to try resaving in another format. Not gonna be fun doing that to thousands of photos, but it's the best i can hope for.

Hopefully an example of one of the photos that won't upload will be included in this post.

How are you uploading? FTP? Via Admin? The Piwigo uploader (which is what I use)?

Not that I'll be able to be of much help, but I'm curious as to why you're having problems, so I can avoid them if at all possible.

JeffPaul wrote:

I suppose I'm uploading via the admin. That is, I'm online at the website/admin with piwigo 2.2.3 and am uploading by clicking "add photos" and then browsing through my computer till i find the folder I want.  Thanks for taking an interest even if you can't actually solve my problem.

When you go into Admin > Photos > recent photos, you see no photos at all?

I'm not understanding this, I guess. You say "till i find the folder". Are you uploading a folder with photos? Or the photos themselves?

Okay, I just tried it, everything uploaded nicely, all .jpg extensions.  But.

I'm getting an error message for every photo uploaded.  See screenshot. 

This shouldn't happen.