What reaching 200 KB costs a PNG

Set 200 KB as the target and the engine works down to it in steps, stopping at the first result that fits rather than padding the file back out.

Resampling comes first, at full colour, because a palette costs more than a few pixels do. Only when scaling alone cannot reach the target is the image reduced to a 256-colour palette. Transparency survives either way: an alpha channel goes in and comes out.

Files are processed on our servers, not in your browser. The upload and the result are both permanently deleted within 1 hour, no backups and no copies kept.

No watermark, and no account needed to use it. 2 files a day at up to 50 MB each, sent singly or together; signing in is free and raises each file to 100 MB.

Protecting the lines and the lettering

1. 1

   Export from the drawing tool, do not capture it

   If the diagram came out of Figma, draw.io, Excalidraw or a charting library, export a PNG at the width you intend to publish. A screen grab of the same canvas carries the surrounding interface and whatever scaling your monitor applied.

2. 2

   Hand over the full width version

   Dimensions are reduced only when the colour palette cannot reach the cap on its own. Submitting the full size export leaves that decision open; downscaling it yourself beforehand closes it off and throws away sharpness you might have kept.

3. 3

   Check the thinnest thing in the picture

   Hairline rules, table borders and small axis numbering suffer before anything thick does. View the result at actual size and look at those. If they held, the rest of the diagram held too.

The target for diagrams that have to stay crisp

A flowchart, an architecture diagram, a bar chart or a wordmark needs to be legible at close to full width, which rules out the tighter targets. 200 KB is where that becomes possible. GitBook, Notion and Confluence all re-encode what you upload, and arriving under 200 KB keeps them from running a second pass over your axis labels and your one pixel connector lines.

Hard edges are what this format is for

Lossy formats work by discarding high frequency information, and a diagram is almost entirely high frequency information. The characteristic failure is ringing: a faint halo of mismatched pixels either side of every black line and letter stroke. On a photograph you never notice it. On a chart with 9 point labels it is the first thing you see.

PNG never does this, because the pixel values it stores are exactly the ones you gave it. Reducing a diagram to an indexed palette changes which colours exist in the image but not where one colour stops and the next begins. That boundary is what makes lettering readable, and it is why a 200 KB PNG of a chart often reads better than a 200 KB JPG of the same chart despite JPG being more efficient per byte in general.

Your logo is probably already small enough

Check the file size before you do anything. A flat colour wordmark at 1600x1600 measured here occupies 21 KB, and asking for 200 KB returns it at 20 KB with the dimensions untouched. There is no work to do on a file like that, and no benefit in pretending otherwise.

A logo that genuinely exceeds 200 KB is not really a flat logo. It has a gradient mesh, a soft shadow, a photographic texture or an embossed effect behind it. Those are the parts that will band when the palette is cut, so if the brand guidelines allow a flat variant, use that file instead of compressing the decorated one.

Destinations that want a different number

Slack renders a PNG inline in a thread up to 500 KB and turns anything heavier into a click to view attachment, so a diagram being shared in a channel belongs on the 500 KB target rather than this one. Amazon Seller Central and Flipkart Seller Hub also accept up to 500 KB before their re-encoding starts, which makes 200 KB needlessly strict for a product listing.

In the other direction, an icon or a cropped detail has no use for this much room. The 100 KB target handles those and loads faster. Match the number to whatever is actually imposing it, and if nothing is, match it to how large the image will be displayed.

Frequently asked questions