Thumbnails, covers, preview videos and metadata for game portals

Every portal asks for store art, and each asks for different sizes, ratios and text rules. The table below lists only what each portal’s public developer docs state as of 2026-09-30. “Not published” means the pages named in the row say nothing about it; some portals show more inside their logged-in dashboards.

Requirements by portal

Portal	Images	Preview video	Metadata fields
CrazyGames	Three covers: 1920×1080 (16:9), 800×1200 (2:3), 800×800 (1:1), visually consistent	Landscape 1080p 16:9 and portrait 1080p 2:3, both mandatory; 15–20 s (cut at 20); max 50 MB; no sound	Description and controls (intro); supported orientations (technical); lobby sizes for multiplayer (multiplayer)
Poki	Static full-bleed 1:1 thumbnail, at least 628×628; needed before a player fit test	Animated thumbnail: .mp4, 1:1, 1080×1080 or more, 50 fps or more, 4–6 s, muted, max 100 MB; added in soft release, required before global release	Not published on the thumbnail, game page or release pages
GameDistribution	JPG (quality guidelines); 512×512, 512×384 and 200×120 mandatory; 1280×720 and 1280×550 optional	Not published	Description and instructions in standard English, 200–500 characters each; distinct title; 1–2 genres and 1–5 tags; age groups (developer guidelines, 5.1–5.5)
GameMonetize	Default image 512×384	Not published	Category, tags, description, how-to-play instructions
Y8	Studio logo, 175×175 recommended; game images not published outside the logged-in Developer Portal	Not published	Studio name and About text; game fields not published publicly
itch.io	Cover 315:250, minimum 315×250, larger such as 630×500 suggested, GIF allowed; screenshots any size, 3–5 recommended	Trailer link: YouTube, Vimeo or SketchFab	Title, short description, genre, up to 10 tags; embed viewport size (HTML5); AI disclosure where it applies
YouTube Playables	Thumbnails in several aspect ratios; exact sizes only inside the Developer Portal	Not published in the public docs	Title, genre, description, publisher and developer information (Developer Portal); accessibility tags recommended

Content rules that differ

Sizes are the easy part. The content rules conflict, so one flat image cannot satisfy all of them:

• Text. Poki advises no text at all, titles included. CrazyGames allows only the game title: no “New”, “Play now” or similar. GameDistribution’s design guidelines suggest putting a title only on the 1280-wide images and no logo on the 200×120. YouTube Playables forbids branding or logos in thumbnails, title and description.
• Borders and framing. CrazyGames and Poki both say no borders; Poki also rules out padding and letterboxing and applies its own rounded corners. GameDistribution lists white side borders, stretched art, cropped-off titles and heavy empty space among its immediate declines.
• Screenshots vs. art. CrazyGames asks for more than a plain screenshot. GameDistribution wants gameplay art or custom designs that reflect the game, not a UI-heavy capture. itch.io recommends real screenshots in addition to the cover, even for embedded browser games.
• Honesty. YouTube Playables bans misleading titles, thumbnails and descriptions. GameDistribution declines misleading or clickbait art. Poki warns that a mismatch between thumbnail and game hurts conversion and playtime.
• Colour. Poki’s page background is #83FFE7; avoid colours close to it.
• Animated covers. itch.io allows GIF covers but asks you to avoid seizure-inducing effects.
• Changes after launch. On Poki, thumbnail changes after the web fit test need Developer Support sign-off.

Build one layered master, export per portal

The ratios in the table include 16:9, 2:3, 1:1, 4:3 (512×384), 315:250, and the 200×120 and 1280×550 strips. Cropping one flat image to all of them cuts off characters or titles, which GameDistribution lists as a decline reason. A workable approach:

1. Keep the key art in a layered source file: background, main character or object, and the title on its own layer.
2. Recompose per ratio instead of cropping blindly. CrazyGames wants its three covers visually consistent; GameDistribution welcomes a different design per size.
3. Export text-free variants for Poki and YouTube Playables, and title variants only where the portal allows them.
4. Check each export at its smallest display size. Poki and GameDistribution both warn that fine detail disappears on small tiles.

Choosing file formats

When a portal names a format, use it: JPG for GameDistribution, .mp4 for Poki’s animated thumbnail. For the rest, the public pages checked here name none, so check the upload form.

MDN’s image format guide gives the trade-offs:

• Lossless encoding suits screenshots, logos and line art, where lossy artefacts around sharp edges and text are very visible. Continuous-tone art usually tolerates lossy compression.
• JPEG is lossy and has no alpha channel. Anything with transparency has to be flattened onto a background before a JPG export.
• WebP and AVIF generally compress better than PNG, JPEG and GIF. Upload them only where the portal accepts them.

Keep masters lossless and export lossy copies last, so repeated edits do not stack compression artefacts.

For video, MDN’s codec guide describes MP4 with AVC (H.264) as a combination every major browser supports. It also notes AVC’s licensing requirements.

Example export commands

These are examples, not portal-approved recipes. Flags were checked against the ImageMagick and FFmpeg documentation linked in the sources.

ImageMagick 7 (magick), a 512×384 JPG for GameDistribution or GameMonetize from a PNG master:

# Example: flatten transparency, fill-resize, centre-crop to 512x384, JPG
magick key-art-master.png -background "#1d2b53" -flatten \
  -resize 512x384^ -gravity center -extent 512x384 \
  -strip -quality 92 gd-512x384.jpg

• -flatten merges the image onto the -background colour, which the JPG needs because it has no alpha.
• In the geometry syntax, 512x384^ treats the size as a minimum while keeping the aspect ratio. -gravity center -extent 512x384 then trims the overflow evenly.
• -strip removes profiles and comments, embedded colour profiles included. -quality at 90 or above keeps JPEG chroma channels at full resolution.

ffmpeg, a Poki-style animated thumbnail from a landscape gameplay recording:

# Example: 5 s from 00:12, centre square crop, 1080x1080, 60 fps, no audio
ffmpeg -ss 12 -i gameplay.mov -t 5 \
  -vf "crop=ih:ih,scale=1080:1080,fps=60" \
  -an -c:v libx264 -preset slow -crf 18 -pix_fmt yuv420p \
  -movflags +faststart poki-animated-1080.mp4

ffmpeg, a CrazyGames landscape preview (18 s, no sound):

# Example: 18 s from 00:30, scaled to 1920x1080, no audio
ffmpeg -ss 30 -i gameplay.mov -t 18 -vf "scale=1920:1080" \
  -an -c:v libx264 -preset slow -crf 20 -pix_fmt yuv420p \
  -movflags +faststart crazygames-landscape-1080p.mp4

• -ss before -i seeks the input, and -t limits output duration (ffmpeg options). -an drops audio, which covers Poki’s “muted” and CrazyGames’ “no sound”.
• The crop filter centres by default, so crop=ih:ih takes the middle square of a landscape frame. scale resizes and fps duplicates or drops frames to hit the rate. Record at 60 fps to begin with; duplicated frames meet the number without adding motion.
• -crf and -preset are libx264 options. -pix_fmt sets the output pixel format. +faststart in -movflags moves MP4 metadata to the file start (formats).
• Check the output size against the limit (100 MB on Poki, 50 MB on CrazyGames). Raise -crf if it is over.

Both ffmpeg commands are exercised by a test in the site’s repository (tests/examples/guide-commands.test.ts). When ffmpeg is installed, it runs them on a short synthetic clip with an audio track, using shorter offsets and durations to fit the clip, and checks that each produces H.264 at the stated dimensions without an audio stream (last run with ffmpeg 7.0). The ImageMagick command was not run.

What to check before you submit

• Every size the target portal lists exists, at exact pixel dimensions.
• Text follows each portal’s rule: none for Poki, title only for CrazyGames, no branding or logos for YouTube Playables.
• No borders, padding, stretched art or cropped-off characters.
• GameDistribution thumbnails are JPG; transparent art is flattened first.
• Preview videos have no audio track and meet length, frame rate and size limits.
• Description and instructions meet GameDistribution’s 200–500 character range where you submit there, and controls name actual keys.
• Tags, genres, platforms and languages describe the game accurately; itch.io may treat pages with irrelevant classifications as spam and restrict them.
• The build itself passes the Portal Readiness Checker; see each portal’s page, such as Poki or CrazyGames, for non-art requirements.

Limits of this guide

Only public developer pages were read. Y8 and YouTube Playables keep their exact image specs inside logged-in portals, and none of the portals here publish accepted upload file types beyond the formats noted. Portal pages change without notice; compare against the linked pages before each submission.