Free online image tool

Resize Image to 300KB

300KB is a comfortable size for a good web image or a detailed document scan. Most upload forms accept it, and it still leaves plenty of room for detail. The tool below opens with 300KB selected, so you can upload and resize straight away.

Free to use · No signup · No watermark

Drop your image here

or click to upload — JPG, PNG and WebP supported

JPEGPNGWebPup to 20MBpaste with Ctrl/Cmd+V

Your image is compressed in your browser and never uploaded.

Understand the limit

What a 300KB Target Means for Quality

300KB is 307,200 bytes. At this size a JPEG around 1500 to 1800 pixels across can usually keep a high quality setting, so compression is rarely obvious unless you zoom in.

This is where the trade between more pixels and more quality becomes a real choice. For an image people will see on a screen, a moderately sized picture at high quality usually looks better than a huge one compressed hard.

Large originals still need work. A 12-megapixel photo usually has to lose some of its dimensions to fit 300KB, and the tool does that proportionally when compression alone is not enough.

Target in bytes: 307,200
Usually for: Web images, document submissions
Good formats: JPG or WebP

Use cases

Typical Uses for a 300KB Image

Website content images

Team photos, event pictures and illustrations placed within a page look sharp at 300KB without weighing the page down.

Document submissions with fine detail

Forms that want a scan of a certificate with a seal, or a handwritten page, need that detail to survive. 300KB gives it room.

Coursework and school portals

Assignment systems that take image uploads sometimes set limits in this range for photographed homework, notes or artwork.

Listings with several photos

On classified and community listings, a few clear photos under 300KB each keep the post quick to open and still show the item properly.

How it works

How to Resize an Image to 300KB

1
Upload a JPG, PNG or WebP
Choose the file or drag it onto the tool. The target field already reads 300KB.
2
Decide on the output format
For photos, keep Auto (JPEG) or choose WebP if the destination accepts it. For a graphic with transparency, Auto keeps the transparency by saving WebP where your browser supports it.
3
Run the resize
Select Resize Image. It usually takes a few seconds, depending on the size of the original and the speed of your device.
4
Check and download
Compare the before and after, then download. If your image was already under 300KB, the tool keeps the original file as it is and says so.

Better results

Practical Tips for the 300KB Range

Match the display size. If a website shows the image 800 pixels wide, uploading one 4000 pixels wide spends most of the budget on pixels nobody sees.
Keep your full-quality file somewhere safe and treat the 300KB version as a copy for this upload.
Watch for banding in skies and smooth walls. If you see it, a slightly smaller image at higher quality usually fixes it. Set the dimensions first with the Image Stretcher, then compress.
Try WebP where the destination accepts it. It tends to show less blockiness than JPEG at the same file size.

Frequently asked questions

How do I compress an image to 300KB online?

Upload the image to the tool above, keep the 300KB target and select Resize Image. Before you download, the result shows the final file size, dimensions and quality.

Is 300KB a good size for website images?

For most images inside a page, yes. It leaves room for good quality at typical content widths. For thumbnails and icons it is far more than you need, and a smaller target will help the page load faster.

Can I get a transparent PNG under 300KB and keep the transparency?

Yes, in most browsers. With Auto selected, an image with transparent areas is saved as WebP, which keeps the transparency and can be compressed. If your browser cannot write WebP, the image stays PNG and may be scaled down to fit.

Why is my 300KB result smaller in dimensions than the original?

Compression alone could not get it under 300KB at full size, so the tool reduced the width and height by the same percentage. The result panel says by how much. For a large, detailed photo this usually looks better than heavy compression at full size.

Does resizing to 300KB change the aspect ratio?

No. When the dimensions are reduced, both sides shrink by the same factor. The image is never stretched or cropped to meet a file size.

Some sites ask for less and some allow more. Pick the size that matches your limit and the tool opens with it selected.