Frequently Asked Questions
Find answers to common questions about PixelTamp’s functionality, licensing, privacy, and troubleshooting.
General & Privacy
Does PixelTamp upload my files or images to any cloud server?
No, never. PixelTamp processes 100% of your media locally on your Mac using native macOS hardware acceleration (AVFoundation, ImageIO) and embedded C libraries (libwebp, Quantizer). There are zero servers, zero analytics, and zero telemetry.
Does PixelTamp require Homebrew or command-line dependencies?
No. Unlike some developer utilities that wrap ffmpeg or imagemagick, PixelTamp is completely self-contained. You do not need to install Homebrew, Python, or external command-line tools. I wanted this app to be accessible to anyone publishing web content.
What are the minimum macOS requirements?
PixelTamp requires macOS 26.0 or later. It runs natively and exclusively on Apple Silicon (M-series processors).
File Processing & Formats
Why did an image become slightly smaller in dimensions?
If you have a dimension constraint enabled (e.g. 2560px or 1920px), PixelTamp scales down images exceeding that threshold while maintaining the exact aspect ratio. Smaller images are never upscaled. To preserve native pixel dimensions, select Original Size before dropping.
Remember, PixelTamp applies it’s dimension constraint to your image’s longest edge.
Why is the output file size larger than the original for certain files?
If a file was already heavily compressed using an aggressive lossy algorithm, re-encoding it at a higher quality profile or converting it to an uncompressed representation may occasionally yield a larger file. PixelTamp displays the exact byte difference for every item in the batch queue so you can review results at a glance.
How does PixelTamp handle transparent PNGs?
PixelTamp’s 8-bit palette quantiser includes full alpha-channel support. Semi-transparent pixels and transparent backgrounds are preserved with high fidelity using Floyd-Steinberg error diffusion dithering.
What does the “Lossless” preset do, and is it mathematically lossless?
- PNG & WebP: Yes, 100% mathematically bit-exact. Palette quantisation is bypassed completely, and full 24/32-bit pixel buffers are compressed using Deflate streams and Google
libwebplossless mode. - GIF: Preserves original palette colour tables and animation frame timings without lossy degradation.
- JPEG & Video (MP4): Delivers visually lossless / transparent high-fidelity output (0.85 quality factor for JPEG, 0.90 hardware quality for MP4) combined with metadata stripping and colour profile normalisation. This strips redundant EXIF headers and colour profiles whilst preserving visual quality that is indistinguishable to the human eye.
- Dimension Note: If a dimension constraint (e.g. 2560px, 1920px) is active and the image is downscaled, the pixel grid is resized to the target dimension. To preserve original pixel dimensions, ensure Original Size is selected.
Can I drop an entire folder of assets?
Yes. When you drop a folder onto PixelTamp, it scans the directory recursively, discovers all supported image and video assets, and enqueues them for parallel batch compression.
Does PixelTamp generate multiple responsive variants (e.g. srcset sets) from one file?
No. PixelTamp is built strictly for 1:1 asset optimisation. It is designed to compress source media or folders of already pre-sized responsive images exported from your design workflow. Generating multi-variant srcset bundles is intentionally out of scope to keep the app focused, fast, and simple.
Troubleshooting & Error States
A file shows “Failed” or “Unsupported” in the queue.
- Ensure the file is not corrupted and can be opened in macOS QuickTime Player or Preview.
- Check that macOS has granted PixelTamp permission to read the source folder.
- If you believe you have encountered an unsupported media format or a bug, please contact support with details about your macOS version and file type.