Why is my screenshot JPG larger than the original PNG?

Screenshots contain sharp text and solid color blocks. PNG compresses these efficiently with DEFLATE, while JPG needs high quality settings to hide artifacts, which increases file size.

Does saving a JPG at quality 100 always make it bigger than PNG?

Not always, but for flat graphics and screenshots, quality 100 can produce a JPG several times larger than the PNG. For photos, quality 100 may still be smaller than PNG.

Can I reduce a PNG file size without converting to JPG?

Yes. If your PNG uses 256 or fewer colors, you can save it as an 8-bit palette image. This often makes it smaller than any JPG version of the same graphic.

What is the best format for logos and icons?

PNG with a reduced color palette or WebP are usually best. JPG tends to be larger for these images because of the way it handles sharp edges and flat colors.

Why Is My JPG Bigger Than the PNG? Causes and Fixes

Converting a PNG to JPG and watching the file size balloon is maddening. It happens because the two formats compress images in opposite ways. Flat graphics, screenshots, and logos are the usual suspects. This guide explains exactly why your JPG ended up larger and exactly what to do about it.

How PNG Compression Works

PNG compression is lossless. It uses the DEFLATE algorithm, which excels at finding long runs of identical pixels. A logo with a solid blue background stores extremely efficiently in PNG. The same applies to text screenshots, where large blocks of the same colour appear. No image data is discarded, so the PNG stays remarkably small for these graphics.

How JPG Compression Works

JPG compression is lossy. It divides the image into 8x8 pixel blocks and encodes each block using a discrete cosine transform. This method targets smooth photographic detail with gradual colour changes. Sharp edges and flat colour areas, the hallmarks of logos and screenshots, create problems for JPG. To hide the artefacts that appear around those edges, the encoder must use higher fidelity settings. Those settings inflate the file size.

Why Your JPG is Larger Than the PNG

Flat Graphics and Logos

PNG compresses solid colour areas perfectly. JPG struggles with them, especially when you raise the fidelity setting to avoid visible ringing artefacts.

Screenshots

A screenshot saved as JPG ending up larger than the source PNG is a common complaint. Screenshots contain text, sharp lines, and solid backgrounds. JPG compression is inefficient for all three.

Maximum Fidelity Settings

Saving a file at maximum JPG fidelity produces a file several times larger than the same image saved at a moderate setting. The encoder tries to preserve nearly all detail, which creates a huge file for graphics with hard edges.

Chroma Subsampling Disabled

JPG normally uses 4:2:0 chroma subsampling, which halves colour resolution in both directions and saves significant space. Disabling subsampling by switching to 4:4:4 increases the JPG file size dramatically.

Compress the PNG Instead of Converting

For a screenshot, logo, or any graphic with few colours, compress the PNG rather than converting it to JPG. A PNG using a limited palette stores as an 8-bit palette image. This produces a file smaller than any JPG version of the same graphic. Most image editors let you reduce the colour depth of a PNG before saving. It is a lossless or near-lossless step that shrinks the file size dramatically.

The rule is straightforward: photos go to JPG. Screenshots, logos, and graphics stay as PNG, compressed, or move to WebP.

Reduce JPG File Size Without Ruining the Image

Lower the fidelity setting. Drop from maximum to a moderate level. The visual difference on a screenshot is minimal, but the file size drops by half or more.
Confirm chroma subsampling is enabled, set to 4:2:0. This is the default in most tools, but some high-fidelity presets disable it.
If the image has large areas of a single colour, add a slight blur or dithering to help the JPG encoder. This is rarely needed for photos but helps with graphics.
Compare the result with the original PNG. If the JPG is still larger, go back and compress the PNG instead.

When JPG Makes Sense

JPG is the right choice for photographs with smooth gradients, natural textures, and fine detail. A colour photo with many shades compresses far smaller as a JPG than as a PNG. For those images, the file-size-increase problem does not occur. The JPG will be smaller, and the fidelity loss is invisible at normal viewing sizes.

A Practical Decision Framework

Choose Your Format

Is the image a photo with smooth colour transitions? Use JPG.
Is it a screenshot, logo, or graphic with flat colours and sharp edges? Keep it as PNG. Compress it by reducing the colour palette to a limited number of colours.
Need the smallest possible file for a graphic? Use WebP. It beats both PNG and JPG for this use case.

Converting Anyway

If you must convert a PNG to JPG, use a tool like pngtojpgconverteronline.com for speed. Just watch for the file-size trade-offs described above.