A complete pass, with the decisions that actually matter
1. Choose a job, then choose photos
“Make a collage” fails when the job is undefined. Examples: two shots that prove a change; four shots that recap a dinner; nine SKUs for a buyer. Gather those files on disk. Convert HEIC. Prefer originals over screenshots of other collages. Two to four pictures for anything that will be viewed on a phone; more only when the board is a contact sheet. If the destination is a swipe, stop and use carousel mode instead — a how-to for a single still will not help a ten-frame post.
2. Box, map, pan
Open Collage Studio (this cluster’s hub). Stay in Single mode. Pick 1:1 for a feed tile, 4:5 for a taller feed, 16:9 for a wide still or thumb. Add the files. Click a layout whose thumbnail matches the argument (pair, hero, equal wall). Drag inside each cell until the subject is centered. Set a background hex if gutters will show. Keep gap modest so you are not manufacturing margins that Instagram will crop anyway. Optional: circle or heart mask when the destination is already round.
3. Export like you mean it
PNG if the cut must stay sharp. JPG 0.92 for photographs you will actually send. Do not screenshot the scaled preview. Rename the download so it is findable. Upload in the destination app, or place the file on a small print if the inch math in the printable spoke allows. If the result is soft, the sources were small or the pan left the subject on a seam — not a missing “HD checkbox.” For school projects, a clean 4-cell 1:1 with readable pictures beats a 16-cell mosaic the projector cannot parse.