What image format, file size and ratio should I use when adding Images to Datablocks?

Any images uploaded to an Image Datablock should follow these guidelines in order to display properly: 

• Supported Formats: JPG, PNG, GIF
  • Only original GIF files are currently supported. If a GIF is cut and resized, a static Image will be displayed on your Datablock
• Maximum File Size: 8 MB
• Ratio: 2:1