What is the difference between lossy and lossless compression?

Lossless preserves every pixel exactly (PNG, lossless WebP); smaller gains. Lossy discards imperceptible detail (JPEG, typical WebP) for much smaller files. Use lossless for graphics with sharp edges and text; use lossy for photos where slight quality loss trades off for speed.

Should I use JPEG, PNG, or WebP on the web?

JPEG is universal for photos but no transparency. PNG is ideal for logos, screenshots, and alpha channels—often larger. WebP gives strong compression with optional transparency and animation support; pair with a JPEG/PNG fallback if you must support very old browsers. After resizing, compare visually at target display size.

How do aspect ratio and cropping interact when resizing?

Locking aspect ratio scales width and height proportionally so the image is not stretched. Fixed width and height without preserving ratio distorts content. Cropping removes pixels before or instead of uniform scaling—use it when the composition matters more than showing the full frame.

Are resolution (PPI) and pixel dimensions the same thing?

Pixel dimensions are the actual width × height in pixels—what the browser paints. PPI/DPI metadata mainly affects print and some design tools; for web performance, file bytes and displayed CSS size matter. A 4000×3000 image shown in a 400×300 box still downloads the full bitmap unless you serve a smaller asset.

How does image weight relate to Core Web Vitals?

Large hero images hurt Largest Contentful Paint (LCP) if they are not appropriately dimensioned and compressed. CLS stays stable when you reserve space with width/height or aspect-ratio. Resizing to the maximum size you actually display—plus sensible compression—directly improves LCP without redesigning the page.

Image Resizer

v1.0.0

Resize and optimize images with multiple modes — exact dimensions, percentage scaling, or fit to width/height. Ideal for web and social media use.

Select Images

Click to select images or drag and drop

PNG, JPG, WebP up to 10MB each

Resize Mode

Width (px)

Height (px)

Target File Size (KB) - Optional

Output Format

Resized images will appear here

Resize and compress images before they hit your CDN or CMS. Right-sized pixels and the right codec cut bytes and improve LCP without changing your stack.

Read the full guide →

Frequently Asked Questions

What is the difference between lossy and lossless compression?: Lossless preserves every pixel exactly (PNG, lossless WebP); smaller gains. Lossy discards imperceptible detail (JPEG, typical WebP) for much smaller files. Use lossless for graphics with sharp edges and text; use lossy for photos where slight quality loss trades off for speed.
Should I use JPEG, PNG, or WebP on the web?: JPEG is universal for photos but no transparency. PNG is ideal for logos, screenshots, and alpha channels—often larger. WebP gives strong compression with optional transparency and animation support; pair with a JPEG/PNG fallback if you must support very old browsers. After resizing, compare visually at target display size.
How do aspect ratio and cropping interact when resizing?: Locking aspect ratio scales width and height proportionally so the image is not stretched. Fixed width and height without preserving ratio distorts content. Cropping removes pixels before or instead of uniform scaling—use it when the composition matters more than showing the full frame.
Are resolution (PPI) and pixel dimensions the same thing?: Pixel dimensions are the actual width × height in pixels—what the browser paints. PPI/DPI metadata mainly affects print and some design tools; for web performance, file bytes and displayed CSS size matter. A 4000×3000 image shown in a 400×300 box still downloads the full bitmap unless you serve a smaller asset.
How does image weight relate to Core Web Vitals?: Large hero images hurt Largest Contentful Paint (LCP) if they are not appropriately dimensioned and compressed. CLS stays stable when you reserve space with width/height or aspect-ratio. Resizing to the maximum size you actually display—plus sensible compression—directly improves LCP without redesigning the page.