RSFrameFit guides
Practical notes for proportional image resizer, including examples and the limits of each workflow.
READ THE GUIDE
Fit, stretch and crop are different operations
Fit mode uses a single scale factor for width and height. If the target box has a different shape, one resulting dimension will be smaller than the limit. This is usually the safest option for documents and product photographs.
READ THE GUIDEA quick check before publishing a resized image
The downloaded dimensions should match the fit you intended. The width and height limits are ceilings, not a promise that both edges will equal the target values.