How to Resize an Image

Resize, crop, flip, or rotate an image — or do it in one click.

6 min read · 调整图片尺寸教程

What does it mean to resize an image?

Resizing an image means changing its pixel dimensions — its width and height. A 4000×3000 photo resized to 1000×750 takes up less space and loads faster, which matters for websites and marketplaces that cap image size.

Resizing is different from cropping: resizing scales the whole image (every part stays, just smaller or larger), while cropping cuts a portion away. You'll often do both — crop to the right frame, then resize to the right dimensions.

How to resize an image online (the fast way)

The fastest method is a free in-browser image editor. Upload the photo, type the new width or height (the other updates automatically when the ratio is locked), and click Apply resize.

It runs locally, so there's no upload wait and no account. You download a clean PNG or JPG at the exact dimensions you typed.

How to resize an image in Photoshop

In Photoshop, go to Image ▸ Image Size, enter the new width or height (make sure the chain icon is on to lock the aspect ratio), and click OK. Then export with File ▸ Export ▸ Export As.

For batch resizing, use File ▸ Scripts ▸ Image Processor, or an action. Photoshop preserves quality best when downscaling; for upscaling, choose 'Resample: Preserve Details'.

How to crop an image to a ratio

Cropping to a ratio gives you a frame that fits a specific slot — 1:1 for a square profile or Amazon main image, 4:5 for Instagram, 16:9 for a banner.

In any editor, set the crop tool to the ratio you need and drag the frame. Our image editor crops to common ratios in one click, or lets you drag a free selection for an arbitrary crop.

How to flip and rotate an image

Flipping mirrors the image — horizontally (left-right) or vertically (top-bottom) — useful for correcting a mirrored selfie or matching a layout. Rotating turns the whole image, usually in 90° steps.

Both are one-click operations in our editor: pick Flip Horizontal, Flip Vertical, or Rotate Left / Right, and the canvas updates instantly.

One-click editor vs doing it by hand

Resizing and cropping by hand in Photoshop or GIMP takes a minute or two per image and a few menu clicks. For a single photo that's fine; for a batch of product photos it adds up.

A browser image editor like deervo handles resize, crop, flip, and rotate in one place, with no install and no signup. Upload, edit, download — and move on to the next shot.

Frequently asked questions

How do I resize an image?

Open the image in an editor, type the new width or height in pixels (most editors keep the aspect ratio locked so the other value updates automatically), then export. In our image editor, upload the photo, enter the dimensions, and click Apply resize — it runs in your browser.

How do I resize an image for free?

Use a free in-browser image editor like ours — no signup, no install. Upload the photo, set the width or height, and download. The resize runs locally, so the file never leaves your device.

How do I resize an image without losing quality?

Downscaling keeps quality; upscaling softens the image because you're adding pixels that weren't there. For small upscales, keep the aspect ratio locked and export as PNG. For large enlargements, use an AI upscaler.

How do I crop an image?

Pick a crop ratio (1:1, 4:5, 16:9) or drag a free selection over the area you want to keep, then apply. Our image editor crops to any ratio in one click — useful for Amazon's 1:1 main image or Instagram's 4:5 frame.

How do I resize a photo on my phone?

Open this page in your mobile browser, upload the photo, set the new size, and download. Because the editor runs in the browser, it works the same on iPhone and Android — no app required.

How do I flip an image?

In an editor, choose Flip Horizontal or Flip Vertical. Our image editor has both as one-click buttons — flip a photo to mirror it, then download the result.

How do I rotate an image?

Use the rotate buttons to turn the image 90° left or right. For a tilted horizon, rotate by a custom angle in Photoshop; for a simple quarter turn, any editor — including ours — rotates in one click.

How do I resize an image to a specific file size?

Image editors resize by dimensions, not bytes. To hit a file-size limit, resize the dimensions down and export as JPG at a lower quality. Most marketplaces ask for specific pixel dimensions rather than a byte size.

Can I resize a GIF?

Resizing an animated GIF keeps its frames, but you need a tool that preserves animation. Our editor handles static images (JPG, PNG, WebP, HEIC); for animated GIFs use a dedicated GIF resizer.

What is the fastest way to resize an image?

A one-click browser image editor. Upload, type the size, download — no software to install and no account to create.