How to Use an Executable Image Viewer to Inspect App Icons and Resources

How to Use an Executable Image Viewer to Inspect App Icons and Resources

Inspecting icons and embedded resources inside executable files (PE on Windows, ELF on Linux, and macOS bundles) is useful for developers, UI designers, and security researchers. This guide shows a clear, step-by-step workflow for using an executable image viewer to locate, preview, extract, and export icons and bitmap resources safely and efficiently.

What an executable image viewer does

• Scan binaries: Lists embedded images, icons, and resource entries inside EXE, DLL, or similar files.
• Preview images: Renders icons at multiple sizes and color-depths without executing the binary.
• Extract/export: Saves icons or bitmaps in standard formats (ICO, PNG, BMP).
• Show metadata: Displays resource identifiers, language codes, and file offsets.

Tools you can use

• Resource editors/viewers (examples): Resource Hacker, IconsExtract, XnView MP (with plugins), Exeinfo PE, or specialized forensic tools.
• For cross-platform or command-line: rsrc2 (Windows resources), icons-from-exe scripts, or binwalk for firmware/ELF.
  (Choose a tool compatible with the target platform and file type.)

Safety first

• Never execute unknown binaries. Viewing resources with a dedicated viewer does not run code, but avoid running the file.
• Work on copies. Always make a copy of the target file before any modifications.
• Use an isolated environment (VM or sandbox) when handling untrusted files.

Step-by-step workflow

1. Prepare the file

   • Copy the executable (EXE, DLL, or ELF) to a working folder.
   • If the file is inside an archive, extract it first.

2. Open the file in the viewer

   • Launch your executable image viewer and open the copied file.
   • The viewer should display a resource tree or list (e.g., ICONGROUP, ICON, BITMAP, PNG resources).

3. Browse available resources

   • Expand icon groups to see all available icon sizes and color depths (16×16 up to 256×256+).
   • Check bitmap and PNG resources for non-icon artwork (splash screens, embedded images).
   • Note resource names/IDs and language codes if present.

4. Preview images at multiple sizes

   • Use built-in zoom or size presets to view how icons render at typical UI scales (16, 24, 32, 48, 64, 128, 256).
   • Verify transparency and color fidelity—some older resources include multiple bit depths or alpha channel variants.

5. Extract or export resources

   • Select the icon or image and choose “Export” or “Save as.”
   • Preferred export formats: ICO for full icon sets, PNG for single-size images with alpha, BMP for legacy bitmaps.
   • When exporting ICO, ensure the exporter preserves all contained sizes and color depths.

6. Verify exported files

   • Open exported icons/images in an image viewer to confirm sizes, transparency, and that no data was lost.
   • For ICOs, test them as application icons in a safe environment to confirm visual correctness.

7. Inspect resource metadata (optional)

   • Check resource IDs, file offsets, and language tags for localization or versioning clues.
   • Some viewers show the raw hex or header info—use that for forensic analysis or further processing.

8. Automate extraction for many files (optional)

   • Use command-line tools or scripts to batch-extract icons from directories of binaries.
   • Verify outputs using a checksum or visual spot-check.

Troubleshooting tips

• If icons appear garbled, try a different viewer—some viewers handle compressed PNG-in-ICO differently.
• Missing large sizes often mean icons rely on system-generated scaling; extract available sizes and use a tool to resample carefully.
• For ELF or macOS binaries, resources may be stored differently (e.g., Mach-O bundles or separate asset catalogs); use platform-specific tools.

Practical uses

• Create app icon previews for stores or design documentation.
• Extract branding assets for localization or theming.
• Verify embedded assets in third-party libraries.
• Assist malware analysts by inspecting non-code assets without execution.

Example quick commands (conceptual)

• Windows GUI: Open file in Resource Hacker → expand ICONGROUP → Export → Save as ICO.
• Command-line batch (conceptual): icons-extract –input.exe –output ./icons/

Final checklist

• Work on a copy.
• Use a trusted viewer.
• Export to appropriate formats (ICO for multi-size, PNG for single).
• Verify visual fidelity and metadata.

Using an executable image viewer is a low-risk, high-value way to inspect and extract visual assets from binaries. With the steps above you can quickly preview, export, and validate icons and images while keeping the original binary untouched.