Prepare a small, intentional selection
Choose two to twelve static JPG or PNG files. The limits are 20 MB per file, 60 MB total and 48 megapixels of source pixels. Remove unrelated screenshots before starting. Names, addresses or notifications that are visible inside a screenshot remain visible in the combined image even though original file metadata is not copied.
Choose a layout for the task
Use a vertical long image for step-by-step instructions, a horizontal strip for a small before-and-after comparison, or a grid for similarly important images. Vertical images share a width; horizontal ones share a height. Grid images fit inside square cells without cropping, so different aspect ratios naturally leave different amounts of blank space.
Review order and spacing
File picker order is not a reliable narrative order. Use Up and Down in the list before creating the result. Gap and margin apply in pixels and share one setting, making the outer border consistent with spaces between images. White works well for documents; black may suit dark screenshots. Transparent pixels are composited onto that background.
Choose readable dimensions
Output width can be 200–4096 pixels. Pictures may be enlarged, so a wide canvas can make a small original look soft. The final image cannot exceed 12,000 pixels in height, 24 megapixels or 50 MB. If a long screenshot hits the limit, reduce width or split the selection into meaningful groups rather than hiding part of the result.
Inspect the actual download
PNG avoids JPEG compression artifacts in fine text and lines. JPEG at 90% encoder quality can be smaller, but it can alter edges and color. Download, inspect the full image at actual size and check the first and last screenshots. Changing the order or settings clears the old result; create a fresh image after each change.