A border can give a photo a defined edge on a pale page. In this tool, it sits inside the existing image, so the outer dimensions stay unchanged.
Image Border Tool lets you choose the thickness and colour. Use it when covering a narrow strip of edge pixels is acceptable.
Thickness uses source pixels
A 400 by 300 image with a 10 pixel border remains 400 by 300. The border covers ten pixels inward from each side. It does not create a 420 by 320 file.
A thickness that looks modest on a large image can overwhelm a small one. The tool rejects a border that is too thick for the available dimensions instead of turning nearly the whole picture into a frame.
Choose a colour that separates the image from its intended background. A white border may be visible against a dark page and difficult to notice against a white one.
Keep important content away from the edge
A caption, hand or product detail near the boundary can be covered. Inspect those areas before accepting the result, especially when preparing a photograph that was already tightly cropped.
Use the Padding tool if the frame must sit outside the original picture. Padding increases dimensions and preserves those edge pixels rather than painting over them.
Batch application uses the same pixel thickness for every image. It does not calculate a proportional border from each image's width, so a mixed batch may look inconsistent.
Check the file at the size where it will actually be displayed. A border can look strong in a large preview and almost disappear in a small thumbnail. The best thickness is determined by that final presentation, not by the input field alone.