For AI agents: markdown of this page — /docs-content-en/ai/chat/vision.md documentation index — /llms.txt

Image analysis

Models with image support accept graphics through the content array with a type: "image_url" element. The image address is either a data: URI with base64 data or an https link. In the GET /v1/models catalog such models carry the capabilities.vision: true flag.

Images are processed for free by bitrix/bitrixgpt-5.5 and bitrix/bitrixgpt-5.5-thinking. Through your own provider key (BYOK), the Anthropic Claude models are available: anthropic/claude-opus-4-6, anthropic/claude-sonnet-4-6, anthropic/claude-haiku-4-5-20251001. For them the platform automatically converts the image_url element to the Anthropic format — nothing needs to change on the client side.

Request example

Terminal 
curl -X POST https://vibecode.bitrix24.com/v1/chat/completions \
  -H "X-Api-Key: YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "bitrix/bitrixgpt-5.5",
    "messages": [
      {
        "role": "user",
        "content": [
          {"type": "text", "text": "Describe what is in the image"},
          {"type": "image_url", "image_url": {"url": "data:image/jpeg;base64,/9j/4AAQSkZJRg..."}}
        ]
      }
    ],
    "max_tokens": 500
  }'

Limits

Parameter Value
MIME types image/png, image/jpeg, image/gif, image/webp
Maximum per image, decoded size 20 MiB
Maximum image_url.url in a request 30 MiB — allowing for base64 encoding, that is 22 MiB of payload
url format data:<mime>[;parameter=value]*;base64,<data> or https://<host>/<path>. Parameters between the type and ;base64 (for example data:image/jpeg;name=photo.jpg;base64,…) are accepted and discarded
http:// links not accepted, only https or data:
Maximum content elements per message 64
Maximum request body per endpoint 30 MiB

MiB is a mebibyte, a binary unit per the IEC 80000-13 standard: 1 MiB = 2²⁰ = 1 048 576 bytes ≈ 1.05 MB. Limits are checked as N × 1024 × 1024, so the error message also states the size in MiB — for example, decoded size 21.3 MiB exceeds limit 20 MiB.

Content check

Before the request is sent to the model, the content of every image_url element passed as a data: URI is inspected by its actual bytes rather than its declared MIME type. If the content is not an image — for example an HTML page or an error response encoded in base64 and declared as image/png — the element is not dropped but replaced in place with the text placeholder [image unavailable: <reason>]. The remaining images are processed normally and the request succeeds.

The content check applies to data: URIs only. A candidate passed as an https:// link is forwarded to the model as is, without fetching or inspecting its bytes — validate such links on your side.

Positions are preserved: the length of the content array does not change, so any candidate numbering on your side stays correct.

The substitution is visible in the response:

  • the X-Image-Parts-Rejected header carries the number of replaced elements — this is the single signal available in every response mode; for streaming responses it arrives with the start of the stream;
  • in a regular (non-streaming) response the warnings field additionally carries an entry with code IMAGE_CONTENT_REJECTED and the substitution details. A streaming response has no warnings field — rely on the header.

Errors

HTTP Code Description
400 invalid_image_payload A structural request error: the url field is missing, the string is neither a URL nor a data URI, a formless data URI (no ;base64,), an unsupported scheme, or http:// in production. The message contains the content element index and the specific reason

Content errors (not an image, corrupted base64, unsupported MIME type, over 20 MiB) no longer fail the request — such an element is replaced with a placeholder (see "Content check").

For the full list of common API errors, see Errors.

Known specifics

The content array is only needed for images. For text requests pass content as a string. An array with a single text element also works but is redundant.

Size is checked after decoding. The 20 MiB limit applies to the image itself, not to the base64 string. The string is roughly a third longer, so the request body is limited to 30 MiB.

See also