Resize an image to exact pixel dimensions
A form or a website often asks for a picture of an exact size, such as 1080 by 1080 pixels. Image size, canvas size and cropping each do a different job, and choosing the right one avoids a squashed or padded result.
Photostr is a free online Photoshop alternative that runs in your browser. There is no account to make, and your photos stay on your device.
Change the image size
Open your picture in Photostr and choose Image → Image Size. Set Unit to Pixels and type the width. With Keep proportions on, the height follows so nothing is stretched. Press OK.
When the shape has to change
If you need 1080 by 1080 from a photo that is not square, do not just untick Keep proportions: that squashes the picture. Crop to the right shape first. Choose the Rectangular Marquee tool (M), set Size to Fixed size in its options and enter the width and height you need. For a large photo, use the same shape at a bigger size, such as 2000 by 2000. Click to place the box, move it into position, then choose Image → Crop to Selection. Finish with Image Size to set the exact pixels.
Canvas size is not image size
Image → Canvas Size changes the area around the picture without scaling it. Use it to add a border or empty space, and choose where the picture sits with Anchor. Making the canvas smaller cuts off the edges.
Save at that size
Choose File → Export As and keep the scale at 100%. Pick JPEG for photos or PNG for graphics and anything with transparency.
Questions
Does making an image bigger add detail?
No. Image Size spreads the existing pixels over a larger area, so a big increase looks soft. Image → AI Upscale can do better on photos, but it cannot recover detail that was never captured.
Will resizing change my text layers?
Text stays editable when Keep proportions is on.
What size should a social post be?
It depends on the platform and changes over time. The start screen templates give common starting sizes, such as an Instagram post and a story.
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