Your images stay on your device.

Image Size Checker

Pick where the image is going, type in its dimensions, and find out whether it will pass before you waste an upload finding out the hard way. If something fails, you get told which tool fixes it. Posting to Instagram is the most common case, so it helps to know the maximum image size for Instagram before you start.

By iwantfreeimagetools.com Team

🔒 Nothing to upload. This works from numbers alone.
Requirements differ a lot between platforms, so this drives every check below.
Right click the file and open its properties or info panel to find these. Leave file size blank if you do not know it.
What happens if my image is the wrong size?

If the aspect ratio is wrong, the platform crops it for you. Almost always from the centre, and almost always badly. This is how people end up with the top of a head cut off in a LinkedIn preview or the bottom of their text missing from a Story. The platform is not trying to be helpful here, it is filling a fixed shaped slot with whatever you gave it.

If the image is smaller than required, it gets stretched. A 600 pixel wide image in a 1200 pixel slot has to invent the missing pixels, and the result looks soft or oddly crunchy. This is the one problem no tool can fix after the fact, which is why the checker tells you to go back to the original rather than upscaling.

If the image is much larger than required, you mostly waste bandwidth. The platform downscales it, which is visually fine, but you have paid for pixels nobody saw. On a website that cost is real, because a heavy image delays the page for every visitor. Serving images at their display size is one of the highest impact speed fixes available.

If the file exceeds the size limit, the upload fails or gets crushed. Some platforms reject it outright. Others accept it and compress hard, which is where blocky patches in skies and flat colour come from. Compressing it yourself first gives you control over where the quality goes.

One thing worth knowing: passing every check here does not mean the platform leaves your image alone. Instagram and WhatsApp re-encode almost everything. Matching the spec means the platform has less reason to resample, which is the most you can control from your side.

Where these numbers come from

Platform requirements change without much notice. These figures were accurate when this page was written, and the safest habit is to check the platform's own current guidance for anything critical.

Tested verdict:

Best for: Checking whether a photo meets Shopee, Lazada or WhatsApp size rules before you upload it, and reading dimensions and file weight at a glance

Limitations: Reports size and dimensions against platform figures that were accurate at the time of writing, so confirm anything critical against the platform's own current guidance

Best suited for: Sellers who keep hitting upload rejections and want to check before trying again

Common questions

What size should an Instagram post be?
A square post should be 1080 by 1080 pixels. Stories and Reels covers use 1080 by 1920, a 9 by 16 ratio. Instagram re-encodes whatever you upload, so giving it the correct dimensions means it has less reason to resample your image and introduce artefacts.
Can I make a small image bigger without losing quality?
Not really. Enlarging means inventing pixels that were never captured, so the result looks soft or artificially sharpened whichever tool you use. If your image is below the required dimensions, go back to the original file and export it again at a larger size rather than upscaling the small copy.
Does file size or pixel size matter more?
They matter for different reasons. Pixel dimensions decide whether the image looks sharp and whether it gets cropped. File size decides whether the upload is accepted and how fast a page loads. An image can pass one and fail the other, which is why they are reported separately here.
What is the best image size for a website?
Match the pixel width to the largest size the image is actually displayed at, then compress. A full width hero rarely needs to exceed 1920 pixels wide, and under about 200KB is a reasonable target. Serving images larger than they display is one of the most common causes of slow pages.
Why does my image look fine on my phone but wrong when I post it?
Usually the aspect ratio. Your phone shows the whole image, while the platform fits it into a fixed shape and crops the rest. A 4 by 3 photo placed into a 9 by 16 Story slot loses a lot from the top and bottom. Cropping it yourself first means you choose what survives.

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