Welcome to the forum! Are you getting an error each time you try to upload, or is the selected image just not showing up in your posts?

One thing you can try is changing your settings in the "Edit Options" section:

First, go to the control panel here: https://www.guitartricks.com/forum/usercp.php?

Next, click "Edit Options" in the menu on the left-hand side of the screen, and select "Show Avatars" in the Thread Display Options