Best fit
You already have a landscape cover and a separate square thumbnail, and want to check their file properties before uploading.
// Digital Products
Gumroad Image Preflight
Inspect a real Gumroad cover and thumbnail pair, render safe-zone previews, and get PASS, REVIEW, or REWORK findings before upload.
Format: Agent skill, not a browser app. You need an AI agent that can load its instructions and use the required tools.
Package requirements: Python 3.9+ and Pillow 10.1+, an agent able to load the supporting helper and run it locally, and supplied PNG, JPEG or WebP images. No Gumroad login required.
You get: A JSON file-fact report, a written PASS / REVIEW / REWORK summary, and two safe-zone preview images.
Licence and access details
Review the package licence at the destination.
This skill is free. Review the connector access and licence on Agensi. You supply the compatible agent and local tools; setup support is not included.
Agensi access: Package 1.0.1 retrieved through the Agensi creator connector and executed in Claude on Linux with Python 3.13.17 and Pillow 12.3.0 on October 26, 2026. Six runs passed: RGB and transparent image pairs, existing-folder and input-folder refusal, and two constrained-write failures. Inputs were unchanged. Buyer delivery and other hosts were not tested.
Your first useful result
Already have artwork? Check the two image files before opening the upload form.
Show the first-run walkthrough
- Prepare. For a separately obtained local package, extract all files. For Agensi, ask your connected agent to load SKILL.md and its supporting files. You need Python 3.9+ and Pillow 10.1+ already available. Place a cover.png and a separate thumbnail.png in the package folder, or substitute your own local paths.
- Run from the package folder.
python scripts/preflight_gumroad_images.py cover.png thumbnail.png --output-dir first-image-check - Review the output. Open review.md for the findings, report.json for the file facts, and cover-preview.png plus thumbnail-preview.png to judge cropping and placement. PASS means the files meet this checker’s review baselines—not that Gumroad has accepted them.
Choose a fresh output folder to avoid replacing previous reports. The helper reads local images and writes its reports and previews; it does not log in or upload. You still decide whether the artwork and crop suit the product.
A JustHandled image pair (1280 × 720 cover; 1254 × 1254 thumbnail) returned PASS on Windows with Python 3.12.14 and Pillow. This is an owner-run example, not a marketplace acceptance test.
Prefer to ask your agent? Copy this starting prompt
Read this package’s SKILL.md. Check my supplied cover and thumbnail without changing the originals. Confirm Python 3.9+ and Pillow 10.1+ are available, then run the helper into a new output folder. Show me the findings and both safe-zone previews. Do not upload or redesign anything.
What problem does Gumroad Image Preflight solve?
A cover can look good in an editor but crop poorly, reuse the same composition for the square slot, contain accidental transparency, or arrive below a useful source size.
Use it to
- Check a Gumroad cover before upload
- Verify a separate square thumbnail composition
- Catch undersized or oddly shaped files
- Review transparency and web color-mode risks
What it returns
- File-fact report for both images
- PASS, REVIEW, or REWORK gate
- Cover safe-zone preview
- Square-thumbnail safe-zone preview
A representative input and result
input A 1280x720 RGB cover and a separately composed 800x800 RGB thumbnail.
result Gate: PASS. Both files are readable web formats, meet the review baselines, use separate compositions, and have generated safe-zone previews ready for visual review.
Access and approval boundaries
- Read access only to the user-supplied local input files.
- Write access only to the selected local output directory.
- No browser, network, credential, account, or environment-variable access is required.
Known limitations
- The baselines are review controls, not a guarantee that Gumroad will accept or crop files unchanged.
- Visual quality, subject placement, and brand suitability remain human decisions.
- Pillow must be available locally to inspect and render the files.
// choose with context
Is Gumroad Image Preflight the right skill?
It returns
A JSON file-fact report, a written PASS / REVIEW / REWORK summary, and two safe-zone preview images.
Do not use it as
Creating artwork, deciding brand quality, uploading images or guaranteeing marketplace acceptance.
Compatibility, access, version, and licence
- Reads or accesses
- Declared local scope: cover.png|jpg|webp, thumbnail.png|jpg|webp, image-preflight/**.
- Compatibility
- Python 3.9+ and Pillow 10.1+, an agent able to load the supporting helper and run it locally, and supplied PNG, JPEG or WebP images. No Gumroad login required.
- Version
- 1.0.1
- Licence
- Review the package licence and seller terms at the linked destination.
Questions
Does it upload images?
No. It performs local preflight only.
Which formats are supported?
PNG, JPEG, and WebP are tested.
Why require a separate thumbnail?
A square slot needs a deliberate composition rather than an automatic crop of a landscape cover.
Does PASS guarantee acceptance?
No. Platform processing and visual judgment remain outside the automated check.
What previews are generated?
A landscape cover preview and a square thumbnail preview, each with an inset safe-zone overlay.
Need to create or upload images instead?
Product Image Creator makes new options, while Gumroad Image Uploader handles the reviewed upload workflow.
Gumroad Image Preflight keeps proof and approval boundaries visible.
The listing includes the tested package, realistic samples, declared permissions, and known limitations.
Get Gumroad Image Preflight on Agensi