Assets and presets

Generate one master at the model's native size, then derive every export deterministically (resize, pad, crop) [community: usausa/mcp-image-generator, appicons]. Presets in presets/assets.yaml encode these recipes.

What a preset promises (vincevangen presets)

Presets earn their keep on what code cannot draw: product-shot, avatar, hero, story, social-square, blog-header, YouTube thumbnail, texture-tile and pixel-sprite. For icons, favicons, logos, designed OG cards, UI illustration and sprite sheets, write SVG/Pillow and use a render as a reference at most.

• Concept only, redraw in code: app-icon, favicon, logo-concept, og-image (as a designed card), ui-illustration, empty-state, sprite-sheet, background-pattern. Agent-written SVG/Pillow beats them today; use the render as a reference. sprite-sheet keeps the label after V6 and V8: its frames are cut, counted and aligned, but one image call draws poses, not a cycle (frames repeat or drift), and each frame sits on its own pixel grid, so pixelate on the whole sheet does not find one. A consistent cycle comes from image-to-video of the idle sprite (then cut the clip's frames), or from code; one clean sprite comes from pixel-sprite.
• Sizes it names are sizes it delivers. A preset whose post names WxH ends with cover:WxH (exact, centre crop) or contain:WxH (no crop) and checks it with size:WxH: hero 1920×1080, og-image 1200×630, blog-header 1800×1200, avatar 1024², social-square 1080², story 1080×1920, product-shot 1600×1200, background-pattern 1024², YouTube thumbnail 1280×720. The renders are smaller (16:9 = 1344×768), so these are Lanczos upscales of up to 1.43×: fine behind copy, soft for print. A size: check alone never drops a variant (n>1 still returns every one); taste checks and the judge do.
• It fills what you left open, never overrides you. lighting (hero, product-shot, avatar; MCP/HTTP/spec lighting, CLI --lighting) replaces the preset's lighting sentence and the style's lighting clause: "from the right" becomes "Lit from the right."; a phrase that names its light ("golden-hour backlight") is kept as written. A subject that already states its lighting ("lit by a single candle") drops the default, with a warning. Other presets have no lighting slot and refuse lighting before any spend: describe the light in the subject there.
• empty-state draws line art by default (line-icon style + "thin consistent lines, one accent colour"); any style replaces both. With n>1 its rubric adds "the image clearly shows {subject}", so an "empty coffee cup" drawn full is rejected.
• sprite-sheet has slots frames (2-16, default 8), layout (row, or CxR such as 4x2: the count becomes C×R and the aspect the nearest to C:R), action (default "a simple walk cycle") and cell (auto, or the frame size WxH / N): params={"frames": 4, "action": "a hop"} (MCP/HTTP/spec params, CLI -p frames=4 -p action="a hop"). The template states the count once. Post is key:auto then slice:{grid}:{cell}: the sheet stays as drawn, and beside it go <stem>/frames/<stem>-NN.png (equal, transparent, standing on one baseline) and <stem>/<stem>.gif (result fields frames, gif; the MCP preview shows the cut frames). The frames:{frames} check counts the figures for free and rejects a sheet with the wrong count.
• texture-tile delivers a seamless 1024x1024 tile: post cover:1024x1024 then tileable (offset by half, minimum-error cut through the old seam, histogram match; free), checks size:1024x1024 and seam:1.3. The FLUX-2 render measures 1.7-2.2 (a visible seam); after tileable 0.85-0.9. Organic materials (cobbles, moss, bark, sand) come out clean. On regular rows (bricks, planks, pavers in courses) the cut has to cross rows that do not line up and shows as a stepped line: draw those in code. It fixes the wrap, not large-scale unevenness (a lighting gradient or one odd stone still repeats visibly), so look at a 2×2 tiling. tileable:repair (paid, one edit:fill call, ledger tag post:repair) is the alternative to tileable: same offset, then Bria gen_fill repaints a 12% band over the old seam cross (mask white = repaint) and only the band is blended back. No cut line; the band's stones can come out a little more regular (evaluation tile 2.20 → 0.88, [measured 2026-10-12]). Not offered where edit:fill is missing (hosted, for now).
• pixel-sprite delivers one game sprite as real pixel art: rendered on flat magenta, post key:auto, trim, pixelate:{grid}:{colors}:outline, trim, checks palette:{colors} and edge_halo:0, exports sprite-2x/4x/8x.png (whole multiples, nearest-neighbour). Slots grid (auto = the art's own grid, or a height in px) and colors (default 24). Models draw "pixel art" as soft blocks 4-10 px wide, rarely a whole number (the evaluation knight: 6.82 px); pixelate finds that pitch and gives each block one colour, so the 759 px knight becomes a 112×111 sprite with 24 colours and alpha 0/255. The art's own grid is usually 60-120 px tall; grid=48 or less reduces by block mode with the outline kept, but detail turns to mush there: for sprites of 32-48 px, draw them in code.

Aspect ratio by use [community: jezweb, Qwen rewriter]

Use	Ratio	Master
Icon, logo, avatar, sticker, badge	1:1	1024²
Hero	16:9 or 21:9	1920×1080
OG image	1.91:1 → generate 16:9, cover-crop	1200×630
Blog header	3:2 or 16:9	1800×1200
Card	4:3	1600×1200
Instagram feed	1:1 or 4:5	1080×1080 / 1080×1350
Story, phone wallpaper, mobile hero	9:16	1080×1920
Poster	2:3
YouTube thumbnail	16:9	1280×720
Default horizontal / vertical	3:2 / 2:3

Snap sizes to multiples of 16 for FLUX (32 for FLUX-2-pro) [vendor: schema]; Qwen-Image native sizes: 1328², 1664×928, 928×1664, 1472×1104, 1104×1472, 1584×1056, 1056×1584 [vendor].

Export size tables [community: platform guides]

• Favicon / web: 16, 32, 48; apple-touch-icon 180; PWA 192 and 512 (maskable: keep content inside the central 80%).
• iOS: App Store icon 1024×1024 PNG, no alpha; device sizes 20-180 pt at 1x/2x/3x. Dark and tinted variants optional.
• Android: adaptive icon 108 dp with content inside the central 72 dp (66%) safe zone; density buckets mdpi 48 → xxxhdpi 192; monochrome layer.
• OG: 1200×630. Twitter/X summary_large_image: same.

Recipes (prompt clauses + post-processing)

• App icon (concept only, redraw in SVG): "single centred [symbol], flat vector style, bold simple silhouette, two colours, a simple uncluttered background, generous padding, content within the central two-thirds". 1:1. Post: square, resize set. Reads at 32 px or it fails. Keep the background clause compatible with a gradient the subject asks for — don't force "solid single-colour".
• Favicon (concept only, redraw in SVG): as above but simpler; at most two colours, thick strokes. Post: rmbg if needed, trim, pad, export 16/32/48.
• Logo concept (redraw in SVG): "minimal vector logo mark, centred, strong silhouette, flat colours, plain white background, generous margin", quoted wordmark on a text-capable model. Treat as a concept; redraw in SVG [vendor: OpenAI].
• Hero / OG: subject on one side, a calm/uninterrupted area of plain colour on the [side] for copy added later in HTML/CSS or post — describe that area visually ("an uninterrupted plain area of soft colour across the left half"), one lighting clause. Never write "title", "headline", "text" or "copy" in the visual prompt itself: FLUX/Gemini read that as a cue and paint fake letters. [vendor: OpenAI, Google minimalist template]
• Cutout / product / sticker: FLUX, Qwen and Gemini emit no alpha. Ask for "isolated on a seamless pure white background, soft even studio lighting, crisp clean edges, faint contact shadow only if wanted", then Bria/remove_background, check halos, trim to bbox [community]. Seedream 5 Pro has background: transparent [vendor: schema].
• Sprite sheet: "sprite sheet, N frames in a single horizontal row (or 4×2 grid), evenly spaced, identical character and scale, plain flat background". Condition on a reference of the character and fix the seed; slice in post (slice:CxR). Pixel art: generate large, then pixelate (snap to the render's own grid, never average) and scale nearest-neighbour [community: scenario.com; measured 2026-10-12]. Animation that must loop cleanly: image-to-video of the idle sprite, not a one-shot sheet [evaluation 2026-10-12].
• Texture tile: "seamless tileable [material], top-down orthographic, flat even lighting, uniform detail, no focal object". The model's edges do not wrap; post op tileable repairs the seam for free (offset + minimum-error cut), seam:<max> measures it. Verify by tiling 2×2 [measured 2026-10-12].
• Product shot: softbox key, 3/4 angle, "seamless light-grey sweep", sharp label, generous padding [vendor: Google product template].
• UI / empty-state illustration: flat or isometric, restrained palette with hex, plain light background, open margins; transparent via rmbg.
• Avatar: head and shoulders, face centred in the middle half so a circle crop keeps the head; plain background.

Post-processing ops (vincevangen post: list)

trim (crop to alpha bbox), pad:<fraction> (transparent margin), square (pad to square), fit:WxH (shrink to fit inside; never enlarges, and says so in warnings when it left a smaller image unchanged), contain:WxH (scale up or down to fit inside, no crop), cover:WxH (scale and crop to exactly WxH), webp (convert, q85 [community: jezweb]). Exports are resized from the processed master with Lanczos; a master that went through pixelate exports nearest-neighbour, and an export entry {name, scale: k} is a whole multiple of the master.

More ops, same list (presets, --post, MCP/HTTP post): resize:<w>[x<h>] (resize:512 keeps aspect, resize:64x64 stretches), rmbg (paid background removal, ledger tag post:rmbg), key:<hex>[:tol] (pixels within tol, default 24, of a colour become transparent, then a 1px defringe; for leftover grey or magenta after a cutout; key:auto[:tol] keys the dominant border colour; a key that reaches under 0.1% of the pixels warns and names the border colour), defringe[:px] (contract the alpha edge and recolour the fringe from the solid pixels), match_color:<hex>[:window_deg] (move the dominant colour cluster's hue and brightness to the target, other hues and greys untouched), slice:<cols>x<rows>[:<w>x<h>] (cut a sheet into equal frames: cells are equal divisions of the subject's box with each cut moved into the nearest background gap, every frame trimmed to one shared box, centred, feet on one baseline; :WxH scales them into that frame size, nearest-neighbour; writes frames/ + a looping GIF beside the file and leaves the image itself unchanged; warns when the sheet shows another number of figures than the grid has cells), tileable (make a texture wrap: offset by about half, a minimum-error cut in a 15% band along each border hides the old seam, histogram matched to the source; the seam before and after goes to params.post_log; tileable:repair = the same offset plus a paid edit:fill inpaint of a 12% band over the old seam, blended back inside the band only, ledger tag post:repair), pixelate[:<height>|auto][:<colors>][:outline] (fake pixel art to real: edge-energy autocorrelation finds the render's pixel pitch, fractional and per axis; each cell becomes one pixel of its most common colour, opaque when half of it is; <height> then reduces by block mode; median-cut palette of <colors> (default 32), alpha 0/255; outline keeps a dark 1 px silhouette edge through the reduction. No grid found: the size is kept and a warning says so. Pitch, size and colours go to params.post_log). Check palette:<n> counts the opaque colours. Typical sprite chain: rmbg, key:808080:20, defringe, trim, pad:0.05, match_color:#ff6a00.