How to Convert PGM to ICO

ICO is the format Windows uses specifically for icons — application icons, file type icons, and website favicons — and a single ICO file can bundle multiple sizes of the same image (commonly 16×16 up to 256×256 pixels) so the operating system can pick the right resolution depending on context. PGM is rarely the source for icon design, since it's built for technical pipelines rather than graphics work, but the conversion process still works the same way: decoding the grayscale pixel data and packaging it into the ICO container Windows expects.

This is mainly useful in unusual situations, such as turning a small grayscale visualization or processed image from a research pipeline into a custom icon, rather than a typical icon design workflow.

1. Install Turbo Batch Image Converter Pro on your Windows PC.
2. Open the app and select Batch Mode for multiple files, or Individual Mode for a single PGM.
3. Drag your PGM file or folder into the app window, enabling recursive folder scanning if needed.
4. Set the "From" format to PGM and the "To" format to ICO.
5. Click Convert. ICO files are written to the output folder, fully offline.

• 100% offline — your research and pipeline output is never uploaded anywhere
• Produces standard Windows ICO files for icons and favicons
• Bulk conversion of entire folders, including sub-folders, in one click
• Multi-core processing for fast handling of large batches
• Option to delete original PGM files automatically after conversion
• No recurring subscription or hidden upload limits