Check image dimensions before a Mac upload

Open the image in Preview, then click the Info button in the toolbar to open Inspector. Compare the displayed width and height with the upload requirement before making changes. Apple’s Preview Inspector guide explains the information available there.

1. Open the image in Preview and show the Inspector. Write down the full image’s width and height. If the upload instructions specify a minimum or an exact size, check each number separately.
2. If you plan to crop, select the area you want to keep. Choose Tools > Show Inspector, click the Crop Inspector button, and select the unit you need. Apple’s crop instructions document this route for viewing a selection’s dimensions. The selected area is the part you are evaluating for the crop, so use those numbers when deciding whether it will meet the requirement.
3. If the image needs adjustment, Preview provides selection cropping and Adjust Size. Its size controls include proportional scaling and resampling. Check Apple’s crop and resize instructions before choosing settings for the required output.

Also compare the shape of the image with the destination’s requested shape. A 1,200 × 800 image has a 3:2 ratio; a square slot is 1:1. Enlarging or shrinking the image proportionally does not turn that rectangle into a square. A crop can change the shape, but it discards part of the scene, so examine the planned selection before committing it. If the subject would be cut off, use a different source image or a different layout when the destination allows one.

For a concrete self-check, inspect the resulting image again in Preview after cropping or resizing. Compare its full-image width and height with the requirement, rather than relying on the dimensions you noted before the edit.

A dimension match alone does not establish that an upload will be accepted if the instructions also require a particular file format or file size. Check those conditions separately. If the Inspector shows a width or height below a stated minimum, the image does not meet that dimension requirement as it stands.

If the edited file still fails an upload, compare the saved file with every stated requirement: width, height, aspect ratio, format, and maximum size. The Inspector answers the dimension question; it cannot certify that a remote form accepts the file. Retain the source image so you can revise the crop or export without starting from an already reduced copy.