Crop versus resize versus compress
Crop deletes pixels outside a rectangle. Resize scales the rectangle you keep. Compress encodes those pixels with fewer bytes. People mix them up and then wonder why an Instagram upload still looks zoomed wrong. If the problem is “too much empty sky,” crop. If the problem is “4000 pixels wide,” resize. If the problem is “2 MB over the cap,” compress (after the first two).
Aspect ratios are the language of platforms. 1:1 profile, 4:5 portrait feed, 9:16 stories, 16:9 YouTube and OG-ish, 1.91:1 some link previews. Cropping to the ratio first, then resizing to the exact pixel spec, beats squeezing in a CMS that will crop for you in a worse place (usually center, often through a forehead).
Composition, not just a box
The rule of thirds still applies: do not leave the subject dead-center unless it is a passport. Leave breathing room for UI chrome—Instagram UI eats the bottom of stories; video players eat 16:9 letterbox. For products, keep the entire object and a bit of margin so marketplace “smart crop” does not clip a corner. For screenshots, crop tight enough that readers are not hunting for the cursor.
PNG alpha: cropping a cutout PNG still keeps transparency inside the remaining box. You are not flattening unless you export JPEG. If you crop a PNG logo and then need JPEG, flatten on the right background first.
Quality and generation loss
Cropping JPEG and saving JPEG again is another encode. Crop from the highest-quality original and save once. If you need many variants (square, story, OG), crop from the master each time, not from the previous crop. PNG crops are lossless in spirit if re-encoded losslessly; browser PNG may still rewrite the file.
Do not crop so tightly that you then upscale. Keep enough pixels for the destination. A 200-pixel crop sent to a 1080 story will look like mush.
Privacy and ToolPin
The editor runs in the browser. IDs, kids’ photos, and unreleased campaigns are not uploaded to toolpin.online. 250 MB limit. No account, no watermark. EXIF GPS often drops on export—good when you crop a home interior for a listing and do not want coordinates still in the file. Use Strip Image Metadata if you need to be sure.
Very large panoramas can be awkward to crop on a phone; use a desktop for precision.
Common specs
Instagram feed portrait: 4:5, 1080×1350. Landscape feed: 1.91:1, 1080×566. Story/Reels: 9:16, 1080×1920. YouTube thumbnail: 1280×720. Facebook/OG: 1200×630. LinkedIn company: often 1.91:1. Always crop subject-aware; the numbers are the frame, not the composition.