Sorry to hear that! This could actually be because I think by default Ribbet is saving JPG images at 96DPI, so the 1200×1200 image is printing at 12.5×12.5″ instead of 4×4″.
If you can manually enter a scaling percentage when printing, you could correct this by scaling it to 32%. If it doesn’t give you this option, you could try opening the image in Chrome (you can drag the image on), selecting Print… (from the 3 dots option menu up the top right) and using the “Custom” scaling setting to do this.
Alternatively you could try saving in PNG format and printing that. Although I’m not certain what DPI the printer will then default to.
A final option is resizing the image from 1200×1200 to 384×384 and printing that (I would use this as a last resort though).
– Regards, The Ribbet Team