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PixelTamp

Presets & Configuration

PixelTamp replaces complicated encoding dials that vary by filetype with three opinionated, carefully calibrated presets.

Personal note from the developer: My professional background is in web development and its associated SysOps. This app is born out of years (decades!) of using photo editing apps and CLI compression tools to optimise images before publishing them online. So this app’s opinionated defaults do come from a lot of experience. Get in touch if you feel they’ve missed the mark though.

These specs are for the nerds out there…

The Three Compression Presets

1. Tamped (Default & Recommended)

The sweet spot between visual fidelity and compact web payload.

  • JPEG: Imperceptible quality loss and, as it’s the primary application workhorse, highly hardware-optimised. Retain HDR information.
  • PNG: Adaptive 8-bit quantisation (256 colours) for graphics and UI assets where safe; or else 24/32-bit lossless with compression.
  • WebP: Imperceptible quality loss via embedded WebP library.
  • Video: Imperceptible quality loss, 192 kbps AAC audio, H.264 web profile with faststart MOOV atom.

2. Lossless (Maximum Fidelity)

Pure mathematical or visually imperceptible optimisation without altering visible pixel quality.

  • JPEG: Visually lossless high-fidelity encoding with metadata stripping and colour optimisation.
  • PNG: Full 24/32-bit lossless compression without palette reduction (high bit depths normalised to standard 8-bit channels).
  • WebP: Intelligent source-matched lossless encoding: mathematical lossless for PNG graphics; visually lossless for JPEG sources to prevent noise ballooning.
  • Video: Extremely high-fidelity quality, 192 kbps AAC audio with faststart MOOV atom.

3. Aggressive (Maximum Byte Savings)

High compression for bandwidth-constrained environments, email newsletters, and non-critical use cases.

  • JPEG: Good quality target for maximal byte reduction.
  • PNG: 8-bit palette quantisation (256 colours) with Floyd-Steinberg error diffusion dithering, potentially losing detail in gradients. Retain alpha transparency.
  • WebP: Good quality via embedded WebP library.
  • Video: Good quality, 128 kbps AAC audio with faststart MOOV atom.

4. All (Generate All Options in One Shot)

Produce Tamped, Lossless, and Aggressive variants simultaneously from a single drag-and-drop ingestion.

  • Ideal when benchmarking compression outcomes side-by-side or generating multi-tier web assets.
  • Files are saved with distinct preset suffixes (for example, photo_tamped.jpg, photo_lossless.jpg, and photo_aggressive.jpg).

You are encouraged to inspect examples of these compressions on the website’s home page.

Independent Dimension & Resolution Controls

Resolution and dimension constraints are independent of the compression preset:

  • Images: Select Original Size, 2560px (default), 1920px, or 1024px.
  • Videos: Select Original Resolution (default), 4K (3840×2160), 1080p (1920×1080), or 720p (1280×720).

Any preset can be paired with any resolution mode. PixelTamp never upscales assets that are already smaller than the chosen threshold.

Custom Size Presets (Universal)

If your workflow requires specific pixel dimensions (such as standard editorial banner widths, social media assets, or custom thumbnail sizes), you can define your own size presets in Settings (Cmd + ,) > Sizes:

  • Proportional Scaling: PixelTamp constrains the longest side of the asset to your specified pixel value while preserving aspect ratio. Smaller assets are never upscaled.
  • Universal Availability: Custom presets apply universally to both images and videos. When created, they appear in both the image Size menu and the video Resolution menu, separated beneath the built-in options by a divider.
  • Optional Custom Naming: Presets can include an optional friendly name (for example, Blog Hero at 1200px renders as Blog Hero (1200px) in pickers).
  • Predictable Output Naming: Processed files are appended with the pixel constraint (for example, hero_tamped-1200px.jpg or clip_tamped-1200px.mp4).

Output Saving Strategies

PixelTamp follows a non-destructive policy by default: it never modifies or overwrites your original source files unless you explicitly enable in-place overwriting.

You can configure output destinations in Settings (Cmd + ,):

Option 1: Suffix Alongside Original (Default)

Tamped assets are written to the exact same folder as the source file, appended with a customisable suffix (default: _tamped).

  • Example: photo.jpg → photo_tamped.jpg
  • If an empty suffix is entered, PixelTamp automatically enforces _tamped as a safeguard against overwriting.

Option 2: Custom Designated Folder

You can select a dedicated folder (such as ~/Downloads/Optimised or ~/Desktop/Tamped) where all processed media will be saved.

  • Preserves original filenames when saved to a separate directory.
  • If the output path would conflict with the source file, a numbered suffix is added automatically.

Option 3: In-Place Overwriting (Optional)

For users processing large media libraries who prefer not to manage duplicate files, PixelTamp offers an optional overwrite feature:

  1. Enable in Settings: Under Settings (Cmd + ,) > File Overwriting, toggle on Allow overwriting original files. A confirmation alert outlines the safety implications.
  2. Per-Run Control: When enabled, an “Overwrite original files” toggle appears in the main window. This allows you to choose on a per-batch basis whether to replace source files in place or save copies alongside.
  3. Atomic File Safety: In-place replacements are executed atomically, ensuring original files remain untouched if compression fails or is cancelled. When converting formats (such as PNG to WebP), the old format is safely replaced once the new file is fully written.

Metadata Handling

PixelTamp provides two metadata handling policies, configurable in Settings (Cmd + ,) > General:

Option 1: Preserve Copyright & Attribution (Default & Recommended)

This mode balances web payload efficiency, personal privacy, and intellectual property compliance:

  • Privacy Protection: Strips privacy-sensitive camera EXIF structures, GPS geolocation coordinates, camera serial numbers, lens specifications, and embedded editing histories to protect your privacy and prevent tracking.
  • Creator Attribution: Retains creator copyright notices, artist/author bylines, credit lines, and rights usage terms across standard media formats:
    • JPEG: TIFF copyright headers and IPTC Core/IIM copyright notices.
    • PNG: Standard Copyright and Author text chunks.
    • WebP: Dublin Core XMP metadata containers embedded via libwebpmux.
    • Video (MP4 / MOV): QuickTime and iTunes-compatible artist and copyright metadata tags.

This default ensures that assets published online remain compliant with commercial stock licensing terms and Creative Commons attribution requirements without bloating files with unnecessary camera data.

Option 2: Strip All Metadata

For workflows requiring absolute anonymity and maximal byte reduction:

  • Strips 100% of auxiliary metadata headers, including all EXIF, IPTC, XMP packets, PNG text chunks, and container tags.
  • Delivers the smallest possible file payload for pure performance.

Automation & macOS Shortcuts

All compression presets, dimension constraints, and format conversions can also be controlled programmatically via macOS Shortcuts and the command line. See the Shortcuts & CLI Automation guide to learn how to configure presets headlessly.