There's a limit on the file sizes accepted now.
Your camera or software should have options for sending and storing your photos - chances are, you are taking pictures at the highest possible resolution, which is what you need to print your pictures, but too large for viewing on a computer screen.
If you shrink your photo to "email" size, the bulletin board should accept it just fine.
Or maybe you have photo editing software like Photoshop or Paint Shop Pro - you can resize your digital photos and save a small version of your photos that are more suitable for email or bulletin boards.
Or (if you have Windows 7, this might be the easiest way) you can find the file in Windows Explorer, right click on the file and click "Preview" A new window will open up with your photo previewed. Click on the Email button above it and you will get a drop-down menu - choose "Smaller 640 x 480" and click "Attach" The program will open a new email for you with the resized picture attached. Right click on the attachment and click "Save As" to save it somewhere on your hard drive.