Does resizing an image reduce its quality?

Resizing down (making an image smaller) is lossless in terms of visible quality — you simply have fewer pixels. Resizing up (upscaling) will soften the image because pixels are interpolated. For lossy formats like JPEG you can also control the compression quality separately.

What is the difference between resizing by pixels and by percentage?

Pixels mode lets you set an exact output size (e.g. 1920×1080). Percentage mode scales the image relative to its current size — 50% halves both dimensions, 200% doubles them.

What does "lock aspect ratio" do?

When locked, changing the width automatically updates the height (and vice versa) to keep the same proportions. This prevents the image from appearing stretched or squashed.

Are my images uploaded to a server?

No. All processing happens entirely in your browser using the Canvas API. Your images never leave your device.

Resize Images Online — Free & Private

Whether you need to shrink a photo for email, hit a specific pixel target for a web banner, or scale up for print, OptiPic's Image Resizer handles it in seconds — entirely in your browser.

Choose exact pixel dimensions or scale by percentage. Lock the aspect ratio so proportions stay perfect, or unlock it for a custom crop-free stretch. Pick from common presets like HD (1280×720), Full HD (1920×1080), 4K (3840×2160), or Thumbnail (150×150) to jump straight to standard sizes.

Drop your image here

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When to resize an image

Web publishing: Large photos straight from a camera can be 4–8 MB and 4000+ pixels wide. Resizing to 1200–1600px wide before uploading to a CMS reduces page weight dramatically without visible quality loss.

Social media: Each platform has recommended dimensions — profile photos, cover images, post thumbnails. Resizing to exact specs avoids platform re-compression artifacts.

Pixels vs percentage: Use pixel mode when you have a hard constraint (a design spec says “800×600”). Use percentage mode when you want to proportionally scale without doing the math — “make this 75% of its current size” is more intuitive in many workflows.

Also try

Social Media Resizer — resize for Instagram, Twitter, LinkedIn and more →

Frequently Asked Questions

Does resizing an image reduce its quality?: Resizing down (making an image smaller) is lossless in terms of visible quality — you simply have fewer pixels. Resizing up (upscaling) will soften the image because pixels are interpolated. For lossy formats like JPEG you can also control the compression quality separately.
What is the difference between resizing by pixels and by percentage?: Pixels mode lets you set an exact output size (e.g. 1920×1080). Percentage mode scales the image relative to its current size — 50% halves both dimensions, 200% doubles them.
What does "lock aspect ratio" do?: When locked, changing the width automatically updates the height (and vice versa) to keep the same proportions. This prevents the image from appearing stretched or squashed.
Are my images uploaded to a server?: No. All processing happens entirely in your browser using the Canvas API. Your images never leave your device.