What is lossless compression?
Definition
Lossless compression reduces an image's file size without discarding any information. When the file is opened again, every pixel is identical to the original. PNG is a common lossless image format.
Why it matters for sellers
Some product images must stay exact: logos, size charts, packaging with small text and cutouts with clean edges. Lossless compression keeps those details crisp, with no blocky artifacts.
The trade-off is size. Lossless files of detailed photos are usually much larger than lossy ones, which slows galleries. Sellers often keep a lossless master and publish a lossy copy for the listing.
How to do it with Instasize
Instasize keeps PNG lossless, and its compressor lets you choose lossy output when you need a much smaller file. You can compare results before downloading.
- Upload your image to the Image Compressor.
- Keep the original format for a lossless file, such as PNG.
- Or choose JPEG or WebP if you need a smaller file and can accept some loss.
- Compare the file sizes, then download.
Related Instasize pages
Examples
Shop logo
A logo with thin lines and flat color is saved as PNG. Lossless storage keeps the edges sharp at any size it is shown.
Archive of original shots
A seller keeps a lossless master of each hero photo, then exports lossy copies for listings and social posts.
Size chart image
A chart with small text is shared as a lossless file, so the numbers stay readable.
Frequently asked questions
Does lossless compression change my image?
No. Decompressing a lossless file gives back exactly the same pixel data. Only the way it is stored on disk is different.
Why are lossless files bigger?
Because nothing is thrown away. Photos have a lot of fine variation, so there is less repeated data to squeeze out.
Is PNG always lossless?
PNG compression is lossless. If an image was already lossy before being saved as PNG, the PNG keeps those earlier flaws but adds none.
Can I make a lossless file much smaller?
Only by a limited amount. For big savings you usually need lossy compression or smaller pixel dimensions.