What does it cost to convert JPEG to PNG?

$0.003 per call, paid in USDC on Base via x402.

How large can the JPEG file be?

Up to 25 MB (26,214,400 bytes). Past a limit the call answers too_large (413).

What happens if the conversion fails?

The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled.

catalogue / tools / Images / JPEG to PNG

Convert JPEG to PNG

To convert JPEG to PNG, send one POST to /v1/image-convert with the JPEG source and "format": "png" in the body. Each call costs $0.003 in USDC on Base via x402, with no account and no API key. The source file can be up to 25 MB.

Endpoint: POST /v1/image-convert
Price: $0.003 per call
Service: image-convert
Docs: /docs/image-convert

01Limits

Limit	Value
Largest source file	25 MB (26,214,400 bytes)
Timeout	60 s
Source formats	AVIF, GIF, JPEG, PNG, SVG, TIFF, WebP
Output formats	JPEG, PNG, WebP
Option quality	default 80

02Example

A real JPEG to PNG run of image-convert.

Request

POST /v1/image-convert
content-type: application/json
payment-signature: <base64 x402 payload>

{
  "url": "https://grist.tools/samples/images/pair-note.jpg",
  "quality": 80,
  "format": "png"
}

Response

200 OK
payment-response: <base64 settlement receipt>

{
  "source_url": "https://grist.tools/samples/images/pair-note.jpg",
  "source_format": "jpeg",
  "format": "png",
  "mime_type": "image/png",
  "width": 556,
  "height": 100,
  "bytes": 3057,
  "image_base64": "iVBORw0KGgoAAAANSUhEUgAAAiwAAABkCAIAAAAqgfyWAAAACXBIWXMAAAsTAAAL..."
}

Source file: images/pair-note.jpg, 5.2 KB (5,346 bytes). Quality 95 JPEG of the same 556x100 raster as ocr-scan.png: two uppercase lines drawn from a hand-written 5x7 bitmap font, SAMPLE SCAN FOR OCR and SECOND LINE 2026. The request sets quality to 80. The recorded run returned 3 KB (3,057 bytes) of PNG, 57% of the source size, with an image of 556x100 pixels. Decoded, the PNG in image_base64 opens with 89 50 4E 47 0D 0A 1A 0A 00 00 00 0D (ASCII PNG).

In the sample itself, the segments before the first scan run DQT, DQT, SOF0, DHT, DHT, DHT, DHT and SOS, and the baseline frame header declares 556 by 100 pixels, 8-bit precision and 3 components. In the returned PNG: its IHDR chunk declares 556 by 100 pixels, 8-bit truecolour RGB and no interlacing. The next chunk is pHYs.

03Format notes

JPEG as a source

A JPEG file holds lossy raster data and has no alpha channel. Grist identifies it by the leading bytes FF D8 FF and never by the content-type header the server sent. Two of the conversion services on these pages read it. image-convert sniffs that signature, confirms the bundled libvips decoder can read the format, then reads width and height off the header so that an image over the shared pixel budget is refused before any pixel is decoded. ocr-image-to-text repeats its own check for the same three bytes before the offline Tesseract engine receives the image. Decoding does not undo JPEG compression: block artefacts become ordinary pixel values, so a lossless re-encode stores that noise along with the picture, and a lossy target compresses it again. Metadata blocks such as EXIF are not copied into image-convert output.

PNG as a target

PNG output is lossless, so image-convert ignores the quality value when PNG is requested. Its encoder options are pinned: the maximum zlib compression level, a fixed effort, adaptive filtering off, palette quantisation off and no interlacing, so identical pixels always deflate to identical bytes. Dimensions are kept and reported in the response, and metadata is stripped. Vector input takes a separate service: svg-to-png renders the document at a caller-set density, which drives the natural raster size, and an optional width or height fits the render inside that box with the lanczos3 kernel, keeping the aspect ratio, before the same pinned PNG options apply. video-thumbnail writes PNG by default through ffmpeg's png encoder; when a width is requested, the height follows the aspect ratio and is rounded to an even number.

04Errors

Code	HTTP
`invalid_input`	`400`
`blocked_target`	`403`
`unreachable_target`	`424`
`upstream_timeout`	`424`
`unsupported_content_type`	`415`
`too_large`	`413`
`unprocessable`	`422`
`internal`	`500`

When each is raised, and what it means for payment: /docs/image-convert.

05Questions

What does it cost to convert JPEG to PNG?: $0.003 per call, paid in USDC on Base via x402.
How large can the JPEG file be?: Up to 25 MB (26,214,400 bytes). Past a limit the call answers too_large (413).
What happens if the conversion fails?: The tool answers with a typed JSON error from the errors table. Payment is settled only after the tool has produced its result; a call that fails inside the tool is never settled.