| .A8 | Cubicomp | Raster Image Files | Cubicomp PictureMaker 3D Animation Data | Unknown Software | Unknown Developer |
| .ABM | Unknown Developer | Raster Image Files | Music Album | Redbana Audition | Redbana |
| .ABT | Braille2000, LLC | Raster Image Files | Annotated Braille Text File | Braille 2000 | Braille2000, LLC |
| .ACCOUNTPICTURE-MS | Microsoft Corporation | Raster Image Files | Windows 8 Account Picture File | Microsoft Windows 8 | Microsoft Corporation |
| .ACORN | Flying Meat, Inc. | Raster Image Files | Acorn Image | Acorn | Flying Meat, Inc. |
| .ADC | Steffen Gutmann | Raster Image Files | Scanstudio 16 Color Image | ESRI ArcGIS for Desktop | ESRI (Environmental Systems Research Institute) |
| .AFL | Piotr Fusik | Raster Image Files | AFLI-editor Picture Image | Recoil | Piotr Fusik |
| .AFX | Auto FX Software | Raster Image Files | Auto FX PhotoGraphic Edges Image | Corel Painter | Corel |
| .AGIF | Image Tools Group | Raster Image Files | Active GIF Creator Project | Active GIF Creator | Image Tools Group |
| .AGP | RL Vision | Raster Image Files | ArtGem Project File | ArtGem | RL Vision |
| .AIC | Erik van Bilsen AudioVisuality | Raster Image Files | Advanced Image Coding File | AIC software (AICSetup.exe) | Erik van Bilsen AudioVisuality |
| .AIS | Extreme | Raster Image Files | Velvet Studio Instrument | Velvet Studio | Extreme |
| .ALBM | Hewlett-Packard | Raster Image Files | HP Photo Printing Software Album File | Unknown Software | Unknown Developer |
| .ANV | Birch Grove Software, Inc. | Raster Image Files | ActivTrak Net View File | ActivTrak | Birch Grove Software, Inc. |
| .APD | ACD Systems | Raster Image Files | ACDSee Photo Document | ACD Systems ACDSee | ACD Systems |
| .APM | Adobe Systems Incorporated | Raster Image Files | Aldus Placeable Metafile Image | GIMP | The GIMP Development Team |
| .APS | Microsoft Corporation | Raster Image Files | Visual C++ Resource File | Microsoft Visual C++ | Microsoft Corporation |
| .APX | Ability Plus Software | Raster Image Files | Ability Photopaint Studio Image | Ability Office | Ability Plus Software |
| .ARN | Microsoft Corporation | Raster Image Files | Autoruns Data File | Microsoft Autoruns | Microsoft Corporation |
| .ARR | Lemkesoft | Raster Image Files | Amber Graphic File | Lemkesoft GraphicConverter | Lemkesoft |
| .ARS | Adobe Systems Incorporated | Raster Image Files | After Effects Render Settings File | Adobe After Effects | Adobe Systems Incorporated |
| .ART | Autodesk, Inc. | Raster Image Files | ArtCAM Model | ArtCAM | Autodesk, Inc. |
| .ARW | Sony | Raster Image Files | Sony Digital Camera Image | MacPhun ColorStrokes | Macphun |
| .AVB | Avid Technology | Raster Image Files | Avid Bin File | Avid Media Composer | Avid Technology |
| .AWD | Microsoft Corporation | Raster Image Files | Microsoft Fax Document | PolyView | Polybytes |
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