How to Compress Screenshots Without Losing Readability

Why screenshots get so big

Screenshots are usually saved as PNG, a lossless format that keeps every pixel. On modern displays, the screenshot also has many pixels: a laptop with a high-density screen may capture an image of 2880 by 1800 pixels, or more, and a full-page capture of a long web page can be taller still. Add fine text and gradients, and the file can reach several megabytes.

For sharing in a chat, a ticket or an email, most of that is more than needed. A screenshot is a picture of an interface that the reader will look at on a screen, and with a few changes it can be a fraction of its size.

Why not just use JPEG?

JPEG is designed for photographs, and it does poorly on text and sharp edges. Its compression works on blocks and discards fine detail, which creates halos and fuzzy outlines around letters. At a low quality, text in a screenshot becomes hard to read. At a high quality, it is fine, but then the file is not that much smaller than a PNG of a simple interface.

Screenshots with photographs inside, such as a social media feed or a product page, are an exception: they benefit from JPEG or WebP. Judge by the content. If the screenshot is mostly text and flat colors, prefer a lossless format or high-quality settings.

Step 1: Reduce the dimensions

The most effective step is to reduce the pixel dimensions. A screenshot taken on a 2x display can often be shown at half the size without losing legibility, if the text was large enough in the first place. Use the maximum size option of the compressor, for example 1600 or 1280 pixels on the longest side, and check that the text is still readable.

Remember that the size of the text matters, not just the size of the image. If the reader has to zoom in anyway, a bigger image is justified. For most chat messages and documentation, 1280 to 1600 pixels wide is enough.

Step 2: Crop to what matters

Cropping removes pixels without any compression at all. Cut away empty margins, browser toolbars and unrelated windows, and show only the part that you are talking about. This makes the file smaller and the point clearer. The operating system's screenshot tools allow you to select a region before capturing, which saves a step later.

Cropping also helps privacy, because you do not accidentally share notifications, tabs or personal details at the edges of the screen. Check the whole screenshot before you send it.

Step 3: Choose the format and quality

For screenshots with mostly text and flat colors, WebP is a good output format. At a high quality, such as 85 to 90, the text stays sharp and the file is much smaller than the PNG. If your recipients may not be able to open WebP, use JPEG at 85 or above and check the text. If the compressor says that the file is already optimized, the PNG could not be made smaller by re-encoding, and you should try a different format or a smaller size.

For screenshots with photographs, a lower quality such as 75 to 80 is usually acceptable. When the screenshot mixes both, go with the setting that keeps the text readable.

Annotated screenshots and graphics

If you add arrows, boxes and labels, do it before the final compression, and compress only once. Each lossy compression adds errors, and colored annotations on a lossy image can develop fringes. If you need to edit the screenshot again later, keep an uncompressed PNG as the master.

For diagrams and screenshots of code, readability is the priority. Consider reducing the dimensions less and the quality less, and accept a slightly larger file.

A quick workflow

Take the screenshot, crop it, and add it to the compressor. Set the maximum size to about 1600 pixels, the output format to WebP or JPEG, and the quality to 85. Look at the thumbnail and the sizes. If the text is not crisp, raise the quality or the size, and if the file is still large, lower them a little.

Because everything happens in your browser, you can safely compress screenshots with private content, such as dashboards, chats or invoices, without sending them to a server.

Finally, name the files so that they can be found again. Operating systems give screenshots names that contain only a date and a time, which says nothing about the content. A short descriptive name helps when a colleague asks which screenshot you meant, and the compressor keeps your file name and adds -compressed at the end.

Handling very long screenshots

Full-page captures of long web pages can become extremely tall images, sometimes tens of thousands of pixels high. Many tools and websites cannot handle them, and they are hard to read anyway. If you need to share a long page, split the capture into sections, or share a PDF or a link instead.

If you must keep one long image, reduce its width to a sensible value such as 1000 to 1280 pixels and compress at a moderate quality. This tool scales images that exceed about 16.7 million pixels in total, which includes very tall captures, so you will see the new dimensions in the list.