The picture must be tiny

I couldn't get my picture to show until I trimmed it down to 60 X 57.

pqe

It's the browser cache

Your update is actually taking, what's happening is when only a small part of a page changes, the browser may not think enough has changed to do a round trip back to the server - so instead to save time it will just pull up the page from the local copy it saved on your device (called the browser cache).

When this happens, you need to tell your browser who is boss and *force* it to flush the cache so it *must* do a round trip to the server and get a fresh page. When you do that you will see that your signature has indeed been updated.

To find out how to flush your browser cache, just Google the name of your browser and the words "flush cache", then follow the instructions. For instance, if you're using Firefox, then Google the words: Firefox flush cache and pick one of the entries, then follow the steps.

You can also try a force refresh, which is generally Ctrl F5 on a PC or Mac. But flush cache is guaranteed to do it. Junior web developers pull their hair out over this issue all the time - I know, I used to manage a team of web developers.

But

When I looked at his post, there was no picture. Is there a delay before the change takes effect?

pqe

Drupal woes

The system has some oddities when it comes to editing your signature. For instance, the flickr logo in my signature, which was sized properly before upload, appears huge if I try to edit my signature line. I resize it down but it won't hold the setting. Some time back I considered adding FB and YT logos along with the flickr logo but trying to size them all was ridiculous. Each time I previewed my work the logo sizes would change. Get one right and the other two were wrong. Fix them and the first one would change. I gave up adding the extra logos. Continued at it until the flickr logo size stuck and never ever edit my signature line again.

It isn't taking...

 just checked his account on a tablet that hasn't seen MRH in some time, and there is nothing there. 

Photo size is a biggie for the program - that may be what is tripping you up. 

Try doing a signature without adding the photo and see what happens.