Verifying artwork survives resource shrinking

isShrinkResources = true can keep a resource entry while replacing its contents with a tiny stub. Two obvious checks both produce confident false verdicts, so go straight to the resource table.

Why the obvious checks lie

method	typical output	why it is wrong
grep APK entry names for art_empty_stats	"0 of 18 present"	release renames files to res/tn.png
match source file sizes against APK entries	"kept 4, not found 19"	AGP re-encodes PNG to WebP, so sizes change

A missing name is not evidence of removal when the toolchain renames by design — the same rule as R8 class renaming.

The check that settles it

Read the actual table, then follow each entry to its renamed file and look at the byte size. A stub is a few hundred bytes; real art is not.

import os, glob, subprocess, re, zipfile
sdk = os.path.expandvars(r"%LOCALAPPDATA%\Android\Sdk")
aapt2 = sorted(glob.glob(os.path.join(sdk, "build-tools", "*", "aapt2.exe")))[-1]
apk = "app/build/outputs/apk/release/app-release-unsigned.apk"
out = subprocess.run([aapt2, "dump", "resources", apk],
                     capture_output=True, text=True, errors="replace").stdout
z = zipfile.ZipFile(apk)
sizes = {n: z.getinfo(n).file_size for n in z.namelist()}
lines = out.splitlines()
wanted = ("art_empty_quests", "ic_rank_monarch")      # names that MUST survive
for i, line in enumerate(lines):
    m = re.search(r"(?:drawable|mipmap)[^/]*/(\w+)$", line.strip())
    if not m or m.group(1) not in wanted:
        continue
    for j in range(i + 1, min(i + 4, len(lines))):    # the file path follows the entry
        f = re.search(r"(res/[\w\.]+)", lines[j])
        if f:
            print(f"{m.group(1):24} {f.group(1):16} {sizes.get(f.group(1), 0)} B")
            break

Expected shape: raster art in the tens or hundreds of KB, vector drawables around 1 KB. Anything at a few hundred bytes for a photo-sized asset is a stub.

Note aapt2 dump resources prints the entry and its file on separate lines, which is why the loop looks ahead a few lines rather than parsing one.

The risk that makes stripping real

The shrinker removes what it cannot see referenced. Static R.drawable.x is visible; a name lookup is not:

rtk grep -rn "getIdentifier|resources.getDrawable" app/src/main --include=*.kt

No hits means no dynamic lookups, so nothing can be silently stripped. Hits mean either tools:keep in a raw/keep.xml, or convert the call site to a static reference — the latter is the real fix.

Pair it with the dex probe

Resources and code shrink separately. Check both before claiming a release is verified:

z = zipfile.ZipFile(apk)
dex = b"".join(z.read(n) for n in z.namelist() if n.endswith(".dex"))
for p in [b"$$serializer", b"YourDto", b"YourDatabase_Impl"]:
    print(p.decode(), "KEPT" if p in dex else "MISSING", dex.count(p))

What this still does not prove

The app runs. Install a debug-signed copy of the release APK and open the screens that show the art — an empty-state illustration is only proven by being rendered. Say which of the two you did.