Image Resizer
Open Image Resizer on Happytails.ai. This view has the same page content and links, with explicit tool capabilities. Read the processing notes before using a tool.
Tool capabilities
{
"id": "resize-image",
"category": "image-tools",
"built": true,
"requirements": "Pixels/percent, aspect lock, fit/crop modes, no unintended upscaling, batch dimensions.",
"implementation": {
"fields": [
{
"key": "width",
"label": "Width (px)",
"value": "",
"type": "number",
"min": 1,
"max": 16384,
"step": 1
},
{
"key": "height",
"label": "Height (px)",
"value": "",
"type": "number",
"min": 1,
"max": 16384,
"step": 1
},
{
"key": "lock",
"label": "Keep aspect ratio",
"value": true,
"type": "checkbox"
}
],
"files": true,
"accept": "image/*,.svg,.avif",
"input": false,
"note": "Runs in your browser. Animated inputs produce a single still image. Supported decoding depends on your browser.",
"experience": {
"automatic": false,
"single": false,
"inputMaxLength": 1000000,
"inputMode": "text",
"label": "Your text",
"placeholder": "Type or paste your input…",
"help": "Up to 1,000,000 characters. Review the settings before running.",
"helpParts": [
"Up to 1,000,000 characters.",
"Review the settings before running."
],
"action": "Resize image"
},
"mode": "explicit",
"interactive": false
},
"execution": "Browser interface",
"api": null,
"browser_agent": {
"supported": true,
"name": "run_current_tool",
"discovery": "WebMCP on the human page in a supporting browser",
"verification": "See audit/API-AUDIT.md; availability is not verification"
}
}Page guide
Give your image the dimensions it needs for its next home.
How to use Resize image
- Choose an image. The settings start with its current dimensions.
- Use a percentage preset or enter a width or height. Keep aspect ratio on to preserve proportions.
- Select Resize image, check the final dimensions, then download your PNG.
How Resize image works
Choose an image, enter a width and height in pixels or pick a 50%, 75% or 100% preset, and Happytails.ai redraws it at the new size in your browser. With Keep aspect ratio on, the height is calculated from the width (rounded to whole pixels), so proportions stay the same. The result is always a PNG file. Input and output are limited to 40 megapixels and 16,384 pixels per side, and animated images become a single still frame.
Before you start
Decide the target width in pixels and whether you need to keep the proportions, and remember the download is a PNG, which can be larger than a JPG photo.
A worked example
For a 4000 x 3000 photo with Keep aspect ratio on, entering a width of 1200 sets the height to 900, and you download a 1200 x 900 PNG.
What to expect
Resize an image to the dimensions you need. Enter a width and height in pixels. With aspect ratio enabled, the width determines the height, so your image keeps its proportions.
Common questions
How do I resize without stretching the image?
Leave Keep aspect ratio on. When you change the width, the height updates to match the original proportions, and the reverse also happens when you edit the height. Turn it off only when you want exact dimensions that differ from the original shape, which will stretch or squash the picture.
Why is my resized file larger than the original?
The tool always saves a PNG. PNG is lossless, so a resized photo that started as a compressed JPG can end up bigger even with fewer pixels. If you need a small photo file, convert or compress the PNG to JPG or WebP afterwards.
Can I make an image bigger?
Yes. You can enter dimensions larger than the original, up to 16,384 pixels per side and 40 megapixels in total. Enlarging cannot add detail that was not captured, so upscaled images look softer or blurry.
Does resizing keep animation?
No. Animated GIF, WebP or PNG files produce a single still image, because the tool draws only one frame. Which formats you can open depends on your browser's built-in image decoding, so an unusual format may not load in every browser.
How do I resize to a percentage?
Use the 50%, 75% or 100% buttons after choosing an image. They set the width and height from the original dimensions, rounded to whole pixels. For other percentages, multiply the original width by your percentage and type the result.