Image Resizer

💡 Tip of the Day

Compress images to reduce file size.

What is Image Resizer

Image Resizer makes it easy to change image dimensions and file size without losing clarity. Need a smaller header image for your site, or a quick 2x version for a social post? The free Image Resizer by FlexiTools.io shows your original and resized previews side by side and lets you control scale, width and height, aspect ratio, quality, and output format. In the next 60 seconds, you can upload a photo, pick Percentage or Dimensions, keep the aspect ratio on, set a quality level, choose JPEG, PNG, or WebP, and download the final image.

How to Use Our Image Resizer

  1. Upload your image
  • Drag and drop or click to upload JPG, PNG, WebP, or GIF. You’ll see Original and Resized previews plus dimensions for each.
  1. Pick a resize mode
  • Choose Percentage for a quick scale (1-500%), or Dimensions to set Width and Height in pixels. Keep Maintain aspect ratio checked to prevent stretching.
  1. Set quality and format
  • Use the Quality slider to fine tune file size - most images look great at 75-92. Choose an Output Format: JPEG, PNG, or WebP.
  1. Apply and download
  • Click Apply Resize to update the preview and new dimensions. Click Download to save the resized file, or New Image to start again.

Why FlexiTools.io Offers the Best Image Resizer

Side-by-side clarity

Original and Resized previews make it simple to see changes before you download.

Flexible controls that matter

Scale by percent or exact pixels, keep or release aspect ratio, and set quality and format for the right balance of look and size.

Fast, private, in-browser

Your image stays on your device. Status messages confirm each step.

FlexiTools.io vs typical alternatives

  • FlexiTools.io: Percentage or pixel-based resize - Alternatives: One fixed mode
  • FlexiTools.io: Quality slider and format choice - Alternatives: No control over output
  • FlexiTools.io: Live preview with dimensions - Alternatives: Blind changes
  • FlexiTools.io: Simple Apply → Download flow - Alternatives: Multi-step wizards

A Deeper Look at Image Resizing, Quality, and Formats

Resizing is about pixels. Fewer pixels mean a smaller file and faster loads. The two paths are simple: scale by a percentage of the original or set a new width and height in pixels. Leaving Maintain aspect ratio on keeps the image from stretching - the height will follow the width so the picture stays natural. Turning it off lets you fit a fixed box, but be careful - stretched photos look off in a feed or on a page.

The Quality slider changes how the image is encoded when you pick JPEG or WebP. Lower quality reduces file size by discarding subtle detail; higher quality keeps more detail at a larger size. For photos, a range of 75-92 usually looks clean. For images with text, logos, or UI, even small losses can blur edges - consider PNG or WebP at higher quality for crisper lines. PNG is lossless, so the quality setting typically has little effect; size is driven mainly by dimensions and image complexity.

Which format should you choose?

  • JPEG: great for photos and gradients, tiny files at mid quality. Not ideal for sharp text or icons.
  • PNG: lossless, best for graphics, logos, and UI screenshots. Larger than JPEG for photos.
  • WebP: a modern choice that often beats JPEG in size at similar visual quality and can be lossless for graphics.

If you’re working for the web, resizing down to the display width is the biggest win. A 4000 px image squashed into a 1200 px slot wastes bytes. Start by matching your site’s content width, then adjust quality. For background on how browsers handle images and drawing, MDN’s overview of the Canvas 2D API is a quick primer. For choosing a format, MDN’s image file type guide explains strengths and trade-offs for each format.

A few practical patterns:

  • Hero banners: set width to your page’s content width or 2x for high-DPI displays - then pick WebP or JPEG around 80-90 quality.
  • Product shots: if they have crisp edges or text overlays, try PNG or WebP at higher quality to avoid halos.
  • Blog images: resize to 1200-1600 px wide, JPEG or WebP at 75-85. This keeps pages light and sharp on common screens.
  • Thumbnails: tiny slots benefit from a clean resize and moderate quality; heavy sharpening isn’t needed when pixels are already few.

Why aspect ratio matters
Eyes notice shape first. When ratio changes, faces look wide or tall, circles become ovals, and brand marks feel off. Keeping aspect ratio on means you set only one dimension and the other follows. If you must fit a box, resize to the nearest dimension and let the platform crop. Your image will feel natural while still fitting the design.

Quality vs size - which moves the needle more?
Resizing down saves more bytes than nudging quality alone. Halving width quarters the pixel count. That’s a big reduction before you even touch compression. Use this simple sequence:

  • Resize to the real display width.
  • Choose the right format for the content.
  • Tune quality only as much as needed.

This approach keeps images crisp and fast without trial and error. And you don’t need a heavy editor for it - a quick pass in the browser does the job in seconds.

Pro-Tips for Getting the Most Out of Resizing

  • Resize first, then lower quality in small steps - you’ll get big savings with fewer trade-offs.
  • Keep aspect ratio on for photos and brand assets to avoid distortion.
  • Prefer WebP for photos when supported and PNG for graphics with sharp edges or transparency.
How do Percentage and Dimensions differ?
Percentage scales the image uniformly by the percent you choose. Dimensions let you set width and height in pixels. With Maintain aspect ratio on, entering one dimension automatically sets the other to keep the same shape.
What does the Quality slider change?
Quality affects how JPEG and WebP are encoded. Lower values reduce file size but can add artifacts; higher values look cleaner but produce larger files. PNG is lossless, so quality has little effect there.
Which output format should I select?
For photos, try WebP or JPEG. For logos, UI, and images with text, choose PNG or high-quality WebP. If you need transparency, use PNG or WebP - JPEG does not support transparent backgrounds.
Will the tool keep my image on my device?
Yes. Resizing runs in your browser, and the previews update before you download. Use New Image to clear the current photo and start another.
Can I force an exact width and height?
Yes. Switch to Dimensions and enter both fields. If Maintain aspect ratio is on, the tool will lock the shape; turn it off to force a box, but be aware this can stretch the image.