Resizing guide
How to Resize a PNG Image Online (Pixels, % or Target KB)
Resizing a PNG sounds simple — until you need exact pixels for a social media spec, want to scale a batch by percentage, or need to hit a file size limit like 200KB for an upload form. PNGmaker's PNG Resizer handles all three modes in your browser, with no server uploads.
Three ways to resize a PNG
- Pixels (px). Set exact width and height in pixels. Lock the aspect ratio to scale proportionally, or unlock to stretch to any dimensions. Social media presets for Instagram, Twitter, YouTube, and LinkedIn are built in.
- Percentage (%). Scale all images by a percentage of their original size — 50% halves the dimensions, 200% doubles them. Ideal for batch processing where every image needs to shrink proportionally.
- Target KB. Set a target file size (like 100KB, 200KB, or 500KB) and the tool uses a binary search to find the best combination of dimensions and compression to hit that limit.
Resizing by pixels — when to use it
Pixel mode is the go-to when you need to match a platform specification exactly. Social platforms are strict about dimensions — submitting the wrong size can result in cropping, rejection, or poor display quality.
- Instagram post: 1080×1080px (square), 1080×1350px (portrait)
- Twitter/X header: 1500×500px
- YouTube thumbnail: 1280×720px
- LinkedIn cover: 1584×396px
All of these presets are built into the PNG Resizer — click a preset button to fill in dimensions automatically.
Resizing by percentage — when to use it
Percentage mode is best when you want to reduce a set of images proportionally without caring about the exact final dimensions. Common use cases:
- Generating thumbnail versions of a photo set at 25% of the original size.
- Batch-reducing screenshots from a Retina/HiDPI screen to 50% for standard web display.
- Scaling all illustrations in a pack consistently without specifying individual pixel sizes.
Resize to target KB — when to use it
Many platforms enforce strict file size limits on uploads. KB mode removes the guesswork: enter the target and the tool does the math.
- Email attachments. Many email clients flag or block attachments over 1MB. Resize to 500KB or 800KB to stay safe.
- Upload forms. Job applications, event registrations, and CMS portals often cap uploads at 200KB or 500KB.
- Etsy and marketplace listings. Etsy has strict image limits; other platforms vary. KB mode adapts to any limit automatically.
Does resizing reduce quality?
Scaling down: No visible quality loss for PNG. PNG uses lossless compression, so scaling down simply removes pixels — the remaining pixels are not degraded. The output is sharp and clean.
Scaling up: Raster images cannot add detail that does not exist. Upscaling a PNG makes it larger in file size and dimensions, but the image will appear softer or pixelated. Avoid upscaling photos — it never improves quality. For logos and icons, a small upscale (110–120%) is usually fine at normal viewing sizes.
Aspect ratio — what happens when dimensions don't match
When you enter custom pixel dimensions that do not match the original aspect ratio, you have two choices:
- Stretch. The image fills the exact dimensions but may appear squished or elongated. Appropriate when you control the display and can tolerate distortion.
- Lock aspect ratio. Enable the lock toggle — changing width auto-adjusts height (and vice versa). The image scales proportionally without distortion.
The PNG Resizer shows a warning when your entered dimensions would stretch the image, so you can decide before downloading.
Try it with PNGmaker
Use the tool flow directly from this guide. The idea is simple: understand the workflow, then get to the result fast.