Convert JPEG to PAT

Photoshop and GIMP use PAT files as reusable pattern presets, so a JPEG must be converted when an image needs to appear in a program's pattern library or tiled-fill tool. The correct output depends on the destination application because .pat is used by more than one, partly incompatible pattern format.

What the JPEG format is

JPEG is a lossy raster format used for photographs, scans, camera exports, websites, and email attachments. Phones, cameras, scanners, web browsers, Adobe Photoshop, GIMP, and most image editors can open and create .jpg and .jpeg files.

A JPEG contains compressed pixels, not a pattern-library definition. Repeated editing and saving can add compression artifacts; converting it to PAT preserves those artifacts rather than restoring lost detail. JPEG also normally has no transparency or editable layer structure.

What the PAT format is

PAT usually stores a pattern tile for repeated fills, textures, backgrounds, brushes, or surface effects. Adobe Photoshop and GIMP both use .pat, but their files, metadata, and supported features are not guaranteed to be interchangeable.

After import, the application repeats the tile across the selected area. PAT is useful when a design program needs a selectable pattern instead of a standalone image, but it is not inherently smaller than JPEG. Its compatibility depends on the program and version that will open it.

Convert the JPEG with GIMP

1. Open the image with File → Open.
2. Crop or resize it to the intended tile dimensions. Remove unwanted borders and use a square canvas when the design will repeat equally in both directions.
3. For a texture that should repeat without obvious joins, use Filters → Map → Tile Seamless when that filter is available. Inspect the result at repeated scale; the filter cannot correct every seam in a photograph with directional lighting or strong perspective.
4. Choose File → Export As, enter a filename ending in .pat, and select Export.
5. Enter the pattern description requested by GIMP and confirm the export. Copy the file to GIMP's patterns folder if it must appear in the pattern dock, then refresh the patterns list or restart GIMP.

GIMP creates a GIMP pattern file. Test it in GIMP before giving it to a Photoshop user.

Convert the JPEG with Adobe Photoshop

1. Open the JPEG with File → Open, then crop or resize it to the required tile size.
2. Choose Edit → Define Pattern, enter a name, and select OK. Photoshop adds the pattern to its current pattern library.
3. Open Window → Patterns and apply the new preset to verify its repetition and appearance.
4. To create a file, open the pattern preset-management command available in the installed Photoshop version, commonly Edit → Presets → Preset Manager. Set the preset type to Patterns, select the pattern, choose Save Set, and save the resulting file with the .pat extension.

If the pattern only needs to remain in the current Photoshop installation, defining it in the Patterns panel is sufficient; exporting a PAT file is unnecessary.

Use an online converter

Convertio and Online-Convert are examples of general conversion services that may list PAT as an output format. Their supported formats and PAT implementation can change, so use one only when its current conversion page explicitly offers .pat and identifies the intended application. Upload the highest-quality source available, choose PAT as the output, download the result, and test it in the destination program.

Online conversion is unsuitable for confidential textures, client artwork, or images that must remain local. General converters may produce a file that has the right extension but cannot be imported by Photoshop or GIMP; the application's own export workflow is more predictable.

Quality and compatibility limits

• Start with the original camera image, PNG, or TIFF when available. JPEG artifacts become part of the repeating tile.
• Large tiles can increase memory use and slow fills; small tiles can make repetition obvious. Test the PAT at the scale used in the final design.
• For transparent areas, remove the background and retain an alpha channel in GIMP or Photoshop before creating the pattern. A normal JPEG cannot supply transparency.
• Flattened PAT output does not preserve the JPEG as editable layers, and it does not retain animation or every Photoshop-specific effect. Check the visible result before export.
• Color profiles may be interpreted differently after import. Compare the pattern in the destination application and convert the source to the required color space first when color matching matters.
• Test the generated file in the exact application and version that will use it. A GIMP PAT may fail in Photoshop, and a Photoshop PAT set may fail in GIMP.