ToolNest · Published 2026-09-24 · Updated 2026-09-24
How to compress an image without an upload
Most “compress my image” sites upload the file. ToolNest’s compressor never leaves the tab: Canvas draws the bitmap and exports JPEG.
Read the before/after sizes
The after figure is the JPEG you will download. If it is larger than the original, the original was already small or was a highly compressed JPEG — raising quality will not help. Lower the slider instead.
Transparency
JPEG has no alpha channel. A transparent PNG will flatten. If you need a cutout, use Background Remover and keep PNG.
Questions
Is “up to 90% smaller” guaranteed?+
No. That only happens on large, lightly compressed originals. The tool shows the real reduction for your file.