Resize, pad, recolor and reshape images — all in your browser. All 4 tools below run locally in your browser — nothing is uploaded.
Images are the case where "runs in your browser" stops being a privacy preference and becomes a practical one. A screenshot of a dashboard, a photo of a document, a design mock under NDA — none of it should need a round trip to someone else's server to be made 200 pixels narrower.
These use the canvas API on your own machine: resizing by exact pixels or by percentage, padding an image out with a coloured or transparent margin, and pulling the dominant colours out of a picture as a usable palette.
Whatever your browser can hold. Processing happens on canvas in local memory, so the ceiling is your own machine rather than an upload limit — multi-megapixel photos are comfortable on a desktop and more constrained on an older phone.
Scaling down is clean. Scaling up cannot invent detail that was never captured, so it softens — for JPEG and WebP output you can also set the quality level and watch the result before saving.
PNG, JPEG and WebP. PNG keeps transparency; JPEG does not, so a transparent margin is flattened to white when you export as JPEG.