@jasongoymer
This is usually caused by uploading images that share the same name as previously uploaded images.
When you upload images to Weebly it's essential they all have completely different names, e.g., 'image 001'; 'image 002' etc. If you delete an image and then replace it do not give it the same name, instead use e.g., 'image 001a'; 'image 002a' etc. The same goes for images in different galleries, even if they're on different pages. They must have completely different names to images in the other galleries. So e.g., names like 'gallery 1 image 001'; 'gallery 2 image 001' etc. Also, in my experience uploading images with underscores in the name can sometimes cause problems.
Hope this helps, Gary
