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Why converting an image does not increase its resolution

Changing an image from JPG to PNG won't add pixels. Learn what conversion changes, how to check dimensions, and what to do when you need a larger image.

Sarah CollinsTools and utilities Tools 4 min read

You convert a small image to PNG, but it still looks blurry when enlarged. Or the file is larger afterward, so it seems as if the image gained quality. Changing the file format does not normally increase the image's pixel dimensions or restore detail that was missing.

Use the Image Converter to change formats, then compare the original and converted image dimensions. This will show whether the pixels changed, or only the way the image is stored.

Check the image dimensions

  1. Open the Image Converter and select the image you want to convert. It supports JPG, PNG, WEBP, GIF, BMP, ICO, and TIFF files.
  2. Before converting, check the original image's width and height in pixels. In Windows 11, right-click the file, choose Properties, then open Details. On a Mac, open the image in Preview and choose Tools › Show Inspector to see its dimensions.
  3. Choose the format you need and convert the image. The converter can process up to 50 images at once.
  4. Check the converted file's width and height using the same method. Compare both numbers with the original, for example, 1200 × 800 pixels.
  5. View both images at the same zoom level. A different file size or a different-looking preview alone does not tell you whether the image has more detail.

What the result means

The width and height are unchanged

The conversion changed the file format, not the image dimensions. A picture that was 1200 pixels wide remains 1200 pixels wide after a normal format conversion. Enlarging it on a screen or printing it larger does not change that count.

The file size changed, but the dimensions did not

File size measures how much storage the image uses, not how many pixels it contains. Different formats store image data differently. JPG and WEBP can use lossy compression, which discards some image information to reduce file size. PNG stores image data without that kind of loss, but a PNG made from a JPG cannot bring back detail the JPG already discarded. A PNG may also take up more space without looking sharper.

The dimensions increased, but the image is not clearer

Some software enlarges an image by estimating new pixels from the ones around them. This is called upscaling or resampling. It can make an image fit a larger space and sometimes look smoother, but it cannot recover real details that were not in the original. Strong sharpening can make edges look more defined without adding trustworthy detail.

The pixel dimensions match, but the print size changed

Pixel dimensions describe the image itself. Print size also depends on how many pixels are assigned to each inch, often called PPI. Changing that print setting can alter the suggested physical size without adding or removing pixels. Check the print layout and scaling settings before assuming the image has changed resolution.

How to get a sharper, larger image

  1. Find the original image. Use the largest, least-compressed version you have. A photo downloaded from a messaging app or copied from a small web preview may already have been reduced.
  2. Avoid repeated JPG conversions. Each lossy save can discard more image data. Keep an untouched original, and use a lossless format such as PNG for intermediate edits when appropriate.
  3. Export at a larger size from the source. If the image came from a camera, design file, or editing app, look for its original or highest-quality export. Increasing the export dimensions helps only if the source contains enough detail for the intended use.
  4. Use an upscaling tool only when necessary. Choose software that explicitly resizes or upscales images. It can create a larger file, but treat newly estimated details as a visual guess, especially for text, faces, and fine patterns.
  5. Match the image to the final use. For a website, start with enough pixels for the displayed size. For a print, check the requested physical dimensions and pixel density. Do not rely on changing PPI alone to make a low-resolution image sharper.

Choose a format for the job

Format conversion is useful when a website, app, or printer needs a particular file type. It is not an image enhancement step. Pick a format based on how you will use the picture:

  • JPG: A common choice for photographs when smaller files matter. It uses lossy compression.
  • PNG: Useful for graphics, sharp edges, and transparency. It does not restore detail from a JPG source.
  • WEBP: A web-friendly format that can store images with or without lossy compression.
  • GIF: Often used for simple animations and limited-color graphics, not detailed photographs.
  • BMP, ICO, and TIFF: Use these when a particular program or workflow requires them. The extension alone does not guarantee a higher-quality image.

Files you open in the Image Converter stay on your device. Conversion can change format and file size, but it cannot recreate detail that the original image never contained.

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