Image Resizer & Format Converter
Resize images, lock or unlock aspect ratio, and convert between JPEG, PNG, and WebP with real output sizes.
Image decoding and export happen on your device. No upload endpoint exists.
Choose an image
Drop an image here
JPEG, PNG, or WebP. Maximum 20 MB. No upload.
Batch queue
0 of 20 files
Everything runs in this tab. Nothing is uploaded.
Batch settings
Aspect ratio is kept for each image.
Preview
- File
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- Format
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- Dimensions
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- Size
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Resize and convert
Aspect ratio is locked.
Result
- File name
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- Actual format
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- Dimensions
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- Size
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- Change
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- Quality
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How to resize an image
Select an image, enter the target dimensions, and choose an output format. With aspect ratio locked, changing width recalculates height and vice versa. Unlocking allows distortion, which the interface warns about.
How to convert image formats
JPEG, PNG, and WebP export depend on browser support. After export, the actual Blob MIME type is checked. If the browser cannot produce the requested format, the tool reports the failure instead of renaming a different format.
Understanding quality and file size
JPEG and WebP quality settings trade size for compression artifacts. PNG does not use the lossy quality slider. Output size is measured after export, not predicted. A result can be larger than the source, especially when resizing upward or changing formats.
Frequently asked questions
Why did transparency become white?
JPEG does not support transparency. When converting to JPEG, transparent areas are filled with the selected background color.
Does upscaling add detail?
No. Increasing dimensions does not recover detail that was not present in the original.
Are image files uploaded?
No. Decoding, resizing, and encoding happen in this browser tab.