Image Resizer

Resize an image to the dimensions you need

Open a JPG, PNG, HEIC, or GIF, choose a sizing mode, and select Resize image. The original and resulting previews let you compare the original with the resized copy. Crop the original in a popup, zoom to inspect details, or drag an enlarged preview to move both views together. GIF crops preserve animation. The tool shows the original and planned output dimensions before processing, then the generated file size. Use the download or save/share control to keep the result. Your original file is unchanged and your image stays on your device.

Choose a sizing mode

  • Width: enter a width in pixels. Height follows the original aspect ratio.
  • Height: enter a height in pixels. Width follows the original aspect ratio.
  • Percentage: scale both dimensions together. At 50%, each side is half as long and the image contains roughly one quarter as many pixels.
  • Exact dimensions: set both sides independently. This can stretch a photo; it does not crop or add padding.

A worked example

A 4,000 × 3,000 photo resized to a width of 1,200 pixels becomes 1,200 × 900. The proportional height is calculated as original height × target width ÷ original width. At 25%, the same photo becomes 1,000 × 750. Fractional results are rounded to whole pixels, with a minimum of one pixel per side.

Image quality and file size

Reducing dimensions is useful for web pages, forms, and email attachments. Enlarging a small image cannot recover missing detail and may soften its appearance. JPG is re-encoded at a fixed high-quality setting; PNG retains transparency. HEIC exports as JPG, or as PNG for images with transparency on the web. Animated GIF keeps its frames and timing, but transparent regions are flattened against white because the GIF exporter uses a limited palette. Resizing does not guarantee a smaller file. The result size is shown after generation.

The original and resulting previews fit your screen and may appear smaller than the files they represent. The output pixel dimensions describe the saved file, not its display size or print dimensions.

Formats, privacy, and limits

This version handles one image at a time, up to 25 MB. Still images may be up to 50 megapixels, with output limited to 8,192 pixels per side and 16 megapixels. Animated GIFs are limited to 120 frames, 1,920 pixels per side, and 4 megapixels for both source and output. Large images can still exceed available device memory; try a smaller source or output if processing fails.

All processing is local. A new image is encoded without copying original camera or location metadata. Keep the original file if you need its metadata or wish to avoid repeated JPEG compression. Batch processing is not supported.

Frequently asked questions

How do I resize without stretching?

Choose Width, Height, or Percentage. The other dimension is calculated from the original proportions and rounded to the nearest pixel. Exact dimensions deliberately allows stretching.

Are my photos uploaded?

No. Resizing and export happen on your device. Image contents are not sent to Isobj or an external conversion service.

Which formats and sizes are supported?

Choose a JPG, PNG, HEIC, or GIF up to 25 MB. Still images may be up to 50 megapixels; output is limited to 8,192 pixels per side and 16 megapixels. HEIC exports as JPG (or PNG when it contains alpha on the web). GIF animation and timing are preserved, with a limit of 120 frames, 1,920 pixels per side, and 4 megapixels. Batch resizing is not supported.

Does resizing preserve transparency and metadata?

PNG transparency is preserved. Animated GIF frames use a white matte because GIF output has a limited palette. A new file is encoded without copying the original EXIF or other metadata. Your original file is unchanged.

Will enlarging improve image quality?

No. Enlarging creates more pixels by interpolation; it cannot recover detail missing from the original. JPG export also uses lossy compression, so keep your original as a master copy.

Does resizing guarantee a smaller file?

No. Pixel dimensions and file size are different measurements. Size depends on format, image content, and encoding. Check the generated file size before saving or downloading.