How to convert PNG files to JPEG

In some situations it makes sense to convert a PNG file to JPEG, for example when the PNG is large and contains photographic elements. A JPEG file will usually be much smaller and is better suited for email sharing or embedding on websites.

Saving as JPEG is always lossy. Visible quality loss is possible, especially with low detail elements such as text, icons, or flat color areas.

Note on file extensions:

• There is no difference between JPEG and JPG. The .jpg extension is a legacy from older Windows versions that limited file extensions to three characters.

What is a PNG file?

PNG is the most widely used lossless raster graphics format on the web. Other formats can also store images losslessly, such as TIFF, but PNG compression is particularly efficient.

PNG is well suited for:

• low detail graphics
• cutouts
• logos
• images with transparency, alpha channel

For photos, PNG is usually not a good choice.

Reasons:

• unnecessarily large file sizes
• limited metadata support, because PNG does not fully support Exif and IPTC standards

Convert PNG to JPEG on Windows

Conversion is possible with built in tools.

• Open the PNG file in Paint
• Select File, then Save as, then choose JPEG
• Set file name and location, then save

Convert PNG to JPEG on macOS

Conversion is also possible with built in tools.

• Open the PNG file in Preview
• Select File, then Export
• Choose JPEG as the format, set the quality level, then save

Converting in the other direction

Converting JPEG to PNG is possible, but it is only useful in specific edge cases, because:

• the output file is usually larger
• no additional image information is created
• no quality improvement is achieved

Batch conversion with image management tools

For large volumes and for controlling JPEG quality settings, an image management tool is recommended. Common options include:

• IrfanView
• XnView
• Adobe Bridge

IrfanView and XnView are free for private use. Commercial use in companies typically requires a license. Adobe Bridge is available for free and supports batch processing.

Online converters also exist. Caution is recommended with browser based services. Uploading image files to third party servers can expose both content and metadata to the operator.