Sometimes it can be unclear how to format Attachment_Fu or Paper Clip resizing of images.

I came across this geometry guide that should help be an quick reference.

% = resize to a percentage

! = absolute resize

@ = maximun area

< = resize if both w & h do not match

> = resize if w or h does not match


  • "x300" resizes to a height of 300

  • "x300>" resizes to a height of 300 if the height is greater than 300

  • "150x100>" resizes to 100 height if height is greater than 100 and resizes the width appropriately

  • "50%" resizes the image 50% of the width and height