2026 Mac Site Favicon and PWA Icon PNG Delivery Decision Matrix: Multi-Size Assets, Maskable Safe Zone, sRGB & Remote M4 Batch Acceptance

Pain points: why icon PNG is three products in one brief

1. Slots disagree on geometry. Tabs need crisp tiny marks; touch icons need 180×180; manifests need 192 and 512—one master rarely fits all three crops.
2. Maskable is not “bigger PNG.” Adaptive launchers mask aggressively; edge-kissing art fails under squircles.
3. Color drifts without a contract. Wide-gamut authoring plus untagged PNG reads wrong on sRGB-first shells; pin ICC policy before batch sips.
4. Volume needs gates. Hash manifests and stat ceilings belong on a worker, not a laptop between meetings.

Align color with the sRGB vs P3 checklist and format policy with WebP / AVIF vs PNG delivery. For safe zones at other ratios see social banner PNG matrix; for native ladders see iOS app icon matrix and ICNS batch checklist.

Slot matrix: favicon, touch icon, manifest, maskable

Pinned macOS steps: sips ladder, magick sharpen, manifest hygiene

Pin ImageMagick builds on the worker and log sips --version per job; adjust ICC paths if your org uses vendor profiles.

Step 1 — Normalize the square master to sRGB

sips --matchTo "/System/Library/ColorSync/Profiles/sRGB Profile.icc" master.png --out master_srgb.png

Match your static PNG ICC rule; if tags must go, use the strip recipe in ICC recompress guide after color match.

Step 2 — Emit deterministic sizes with sips

sips -z 32 32 master_srgb.png --out favicon-32.png
sips -z 180 180 master_srgb.png --out apple-touch-icon-180.png
sips -z 192 192 master_srgb.png --out pwa-192.png
sips -z 512 512 master_srgb.png --out pwa-512-any.png

Emit 16×16 only for legacy .ico bundles; otherwise 32 plus SVG is enough.

Step 3 — Optional micro-sharpen for favicon pixels

magick favicon-32.png -colorspace sRGB -filter Lanczos -resize 32x32! -unsharp 0x0.45+0.45+0.006 favicon-32-sharp.png

Keep radius small to avoid halos. Skip sharpen on soft 512 maskable art.

Step 4 — Maskable master with explicit padding

Scale the mark so its box sits inside the 80% diameter circle. Proof in Chrome DevTools → Application → Manifest maskable preview.

Step 5 — Wire HTML and manifest with matching hashes

shasum -a 256 pwa-512-any.png >> icons-manifest.sha256

Wire link rel="icon", apple-touch-icon, and manifest to the same hashed filenames; bump cache keys on rename.

Remote Mac M4 batch acceptance checklist

1. Geometry lock: WxH matches spec with zero slack on ladders; reject odd sizes when the manifest promises even squares.
2. sRGB compliance: magick identify -verbose shows Colorspace: sRGB plus agreed ICC handling on a sample per size class.
3. Byte ceilings: starter bands: 32 ≤ 12 KB, 180 ≤ 45 KB, 192 ≤ 55 KB, 512 any ≤ 180 KB, 512 maskable ≤ 220 KB—tune per CDN.
4. Sharpen audit: log every -unsharp triple in JSONL for diff-friendly review.
5. Install smoke test: Add to Home Screen on Android Chrome and iOS Safari from staging; archive screenshots.

Citable thresholds and policy lines

• Maskable safe circle: diameter 0.8 × min(width,height) centered in the square; treat everything outside as disposable under mask.
• Touch icon margin: default ≥10% padding; move toward 14% for hairline strokes.
• Gate snippet: test "$(stat -f%z pwa-192.png)" -le 55000 for a 55 KB cap—swap the number per SKU.

FAQ

One 512 for any and maskable? Only if padding already satisfies maskable rules; else ship two manifest rows to avoid Pixel clipping.

Touch icon looks darker? Re-run sRGB match and compare design export gamma with Safari on a profiled display.

Next steps: rent a remote M4 for overnight icon sweeps

After a rebrand, a remote Mac mini M4 reruns sips, magick, and stat gates across many tenants with one toolchain. Visit MacPng, review plans, open Help for access steps, and read Tech Insights for related matrices.