Can I upload a 72 DPI PNG if the pixel dimensions match?

No — Sticker Mule’s checks look at both pixel dimensions and DPI. A 72 DPI file that appears large may still be raster-resampled or flagged. Export at 300 DPI with the correct pixel dimensions (for example, 900 x 900 px for a 3x3 sticker) to avoid automatic flags and ensure print-sharp output.

Why does a PDF with vectors still look soft after printing?

Soft output usually comes from one of three causes: fonts weren’t outlined and substituted, effects were rasterised during PDF export, or linked raster images were low resolution. Re-export as a true vector PDF, outline text, remove drop-shadow raster effects, and embed high-res placed images to prevent softening.

How much bleed do I need for small stickers?

Sticker Mule expects a small but consistent bleed: 0.0625 inches (1.6 mm) on small stickers. That keeps the cutter from trimming into artwork when registration shifts. Add the bleed on export or use a separate bleed layer in your master and verify with a dieline preview.

Is PDF always better than PNG?

PDF is better for vector art, dielines and packaging because it preserves paths and text. PNG is preferable for raster art that needs transparency (die-cuts, holographic layers, mug/tee zones). Choose PDF when you need sharp edges and PNG when you need transparent pixels.

What’s the fastest way to prepare one design for multiple SKUs?

Keep one layered master at high resolution, then export presets per SKU: a 900x900 PNG for 3x3, 1500 px min PDF/PNG for die-cuts, 2400x3000 PNG for mugs/tees, and vector PDFs for packaging. Use the master layers to toggle dielines, cut paths and effects so you don’t rebuild assets for each product.

Will Sticker Mule accept RGB PDFs?

They do accept RGB PDFs, but if you’re designing packaging or print-critical dielines it’s best to export with a print (CMYK) profile where possible. When in doubt, export a high-quality vector PDF and include an RGB PNG alternative so you can compare proofs.

Platform Guide

Print-Ready Images for Sticker Mule

A practical, no-nonsense upload spec for sellers using Sticker Mule. Focused on exact pixels, required bleed, and the usual reasons files get flagged.

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I’m Mac, founder of Ratio Ready and a sticker seller since 2020. Sticker Mule sits between fast-turnaround custom printing and a strict proofing workflow — it’s great when you need premium stickers, magnets, packaging or apparel without a marketplace listing. If you sell on other platforms, this sheet complements our /print-ready/printful cross-reference and saves re-exports later.

Below are the exact pixel targets, formats, bleed rules and the rejection patterns I see most often. If you need to check resolution before exporting, run your master through our DPI Checker so you don’t waste upload attempts.

Sticker Mule — Upload Spec Table

Use this table as your single-source checklist before export. I keep one layered master and export per row below. When Sticker Mule accepts both PNG and PDF, prefer PDF for vector edges and PNG for raster with transparency.

Product	Pixel Dimensions	DPI	Format	Notes
Custom Stickers (3x3 in)	900 x 900 px	300	PNG (transparent)	Minimum sticker size; transparent PNG with 0.0625 in (1.6 mm) bleed
Die-Cut Stickers (large)	1500 x 1500 min px	300	PNG / PDF	Larger custom shapes; prefer PDF for vector edge sharpness
Kiss-Cut Sticker Sheets	Up to 8.5 x 11 in @ 300 px	300	PDF / PNG	Multiple stickers per sheet; vector PDF preferred
Holographic / Glitter	1500 x 1500 min px	300	PNG (transparent)	Same as die-cut; specialty finish applied in-house
Mugs / T-shirts	2400 x 3000 print area px	300	PNG (transparent)	Standard 11oz mug / adult tee print zone
Pouches / Packaging	Varies by SKU px	300	PDF / AI	Vector preferred for custom dielines; export with crop marks and dieline layer

If you maintain an Etsy or Printful presence, compare these pixel targets to your exports in /print-ready/etsy and /print-ready/printful — that helps avoid double work when you re-use assets across platforms.

Color Profile and File-Format Strategy

Sticker Mule accepts PNG and PDF uploads but the final press work is vector-friendly and benefits from embedded profiles. My rule: export raster art as sRGB PNG at 300 DPI, and export packaging or dieline work as vector PDF with an embedded CMYK or print ICC if your editor supports it.

PNGs: Use sRGB, 300 DPI, transparency enabled. Good for die-cuts, holographic overlays and mug/tee zones.
PDFs/AI: Use for dielines, text, and vector shapes. Embed fonts or outline them to avoid substitution.
ICC profiles: If you can embed a CMYK profile in exported PDFs (your design app often offers it), include it for packaging work; otherwise deliver high-quality vector paths.
Why this mix: Raster PNGs keep transparent cutlines simple; PDFs keep edges razor-sharp and avoid rasterisation that softens lines.

Before you export, validate pixel density with the DPI Checker and follow the steps in How to convert image to 300 DPI if you’re upscaling older art. When possible keep a layered master so you can re-export per SKU without repeated edits.

Most Common Rejection / Quality-Flag Reasons

I see the same failure modes most weeks. Knowing them saves time and re-uploads.

Too-small artwork: Files with the longest edge under 1500 px are auto-flagged for stickers. Even if the physical size is small, Sticker Mule’s auto-check expects minimum pixel counts for reliable press output.
Raster where vector preferred: PDFs that contain embedded raster effects or flattened strokes can rasterise at print time and produce soft edges. Export true vector PDFs for dielines and text.
Missing transparency: Die-cut stickers uploaded as non-transparent PNG/JPG become rectangles. Always export a transparent PNG or a PDF with a clear dieline layer.
Insufficient bleed: Missing the 0.0625 in (1.6 mm) bleed on small stickers causes white slivers or trimmed artwork. See How to add bleed to print files for quick fixes.
Embedded effects and low-res linked assets: Drop shadows, glows or low-res placed images inside PDFs can force downsampling; flatten only where necessary and replace low-res links with high-res originals.

If you want cross-platform advice about formats for marketplaces, our Best image format for Etsy listings guide highlights differences that affect re-use.

Workflow: One Master, Many Sticker Mule Products

Keep a single layered master file and export according to the table above. This minimizes layout errors and keeps colors consistent between stickers, mugs and packaging.

Create the master: Work at the largest required target — I use a 3000 px wide artboard at 300 DPI so you can downscale without resampling artifacts. Keep artwork on separate layers (artwork, dieline, cut path, effects).
Make export presets: Save PNG-300 (sRGB, transparency) and PDF-vector presets in your editor. Use the PDF preset for sheets and packaging dielines to preserve vectors.
Export per SKU: For a 3x3 custom sticker export 900x900 PNG with 0.0625 in bleed; for die-cuts export a 1500 px minimum PDF with vector cut path. For mugs/tees export 2400 x 3000 px PNG cropped to the print zone.
Check resolution and bleed: Run the exported files through the DPI Checker and verify bleed with How to add bleed to print files. If you retarget DPI, follow these conversion steps to avoid resampling artifacts.
Test upload and proof: Upload the smallest SKU first (3x3) so Sticker Mule’s auto-check catches pixel/bleed issues quickly. Keep a changelog in your master when you tweak cut paths or spot colors.

If you also sell wall art or other goods, check the /for/print-on-demand-sellers use-case notes for reusing master files across marketplaces and print partners.

Quick Checklist Before Upload

Before you hit upload confirm these four things: 1) Correct pixel dimensions and 300 DPI, 2) Transparent PNG or vector PDF with cut path, 3) 0.0625 in bleed on small stickers, 4) No embedded low-res rasters in PDFs. Keeping that checklist next to your export presets saves hours.

Run a final DPI check with DPI Checker.
Compare exports with your /print-ready/etsy or /print-ready/printful presets if you sell across platforms.
Keep a layered master and a log of changes to cut paths and dielines.