Crop, fit or stretch — which one to use
Resizing to a different shape always forces a choice, because the pixels you have don't match the frame you want. Crop to fill scales the image until it covers the whole frame and trims what spills over. It's the right choice for almost every social post: no empty bars, and the subject stays the same size as the frame changes. Use the anchor grid to decide which part survives — top for a portrait whose face is near the top, centre for most product shots.
Fit inside keeps the entire image and fills the leftover space with a colour you pick (or transparency, if you export PNG or WebP). Use it for logos, screenshots and anything where cutting off an edge would lose information. Stretch forces the image into the frame and distorts it — useful only when the ratio is already almost right.
Which format should I download?
JPG is the safe choice for photos: small files, supported everywhere. PNG is lossless and keeps transparency, so use it for logos, graphics with sharp text and anything with a transparent background — at the cost of larger files. WebP gives JPG-like quality at a noticeably smaller size and supports transparency; it's ideal for websites, and every modern browser reads it.
The quality slider only affects JPG and WebP. Between 80 and 90 is the sweet spot: below 70 you start to see blocky artefacts around edges and text; above 92 the file grows quickly for very little visible gain.
Why upload at the platform's exact size
Every platform re-compresses what you upload. If your image is larger than it needs to be, the platform shrinks it with its own settings — often softening text and fine detail. If it's smaller, the platform scales it up and it looks blurry. Uploading at the recommended size means the platform has as little work to do as possible, and your image looks the way you exported it.
Your image never leaves your computer: the resizing runs in your browser using the canvas built into it. There is no upload, no queue and no file-size limit beyond what your device's memory can handle.