ComfyUI Node

Qwen2.5-VL-3B-Instruct

Ask a vision model about your image, get a string back

By Runware·Created 2 years ago·Updated about a month ago· 140
Qwen2.5-VL-3B-Instruct
  • image
  • text
prompt

The Runware pack has exactly one node that behaves like a chat you can point at a picture, and it's this one: Runware_alibaba_qwen2_5_vl_3b_instruct runs Alibaba's Qwen2.5-VL vision-language model (runware:152@1) in the cloud. You wire in an image, optionally type a question, and it returns a text answer as a STRING. Two inputs, one output, no VRAM involved - the entire node is a question-asking tool.

Which is genuinely useful, once you stop looking for drama. A vision model in the graph is the missing piece for automations: it's how you describe images you didn't prompt yourself, check what a generation actually contains, caption a batch for sorting, or answer "is there a cat in this frame?" before routing the result somewhere. It's the text side of the pack's IMAGE-in / STRING-out utilities, and it pairs naturally with the caption-style nodes around it.

How it works

image (required) is your visual input as a plain IMAGE tensor. prompt (optional) is your instruction or question - "describe this image," "what's the text on the sign?", "is the subject looking at the camera?" - anything you'd ask a vision model. Leave the prompt empty and the model produces a default description. The answer comes back on the single text output: a STRING you can display with a Text node, log into a report, or feed into workflow logic that consumes strings. That's the whole loop.

What it's actually good for

  • Batch captioning - feed a folder of generations through it and collect descriptions, no manual reviewing.
  • QC checks - ask it yes/no questions ("is there a watermark?", "are there more than two people?") and branch on the answer.
  • Prompt reverse-engineering - have it describe a reference image in the style of a prompt, then feed that into a generation node.
  • It's the 3B Instruct tier - small, fast, cheap, and a bit less deep than the big VLMs. For description and simple QA it's plenty; for multi-step visual reasoning you'd want the bigger siblings.

The honest notes

  • It's a network call. Small model, but it's still cloud inference with a round trip and a per-run cost on the title bar. Great for automations, overkill if you just want one description - though honestly, one call is a fraction of a cent.
  • Prompt quality is still a skill. "Describe this image" gets a generic description; "Describe the lighting, mood, and composition" gets something you can actually use. Same prompting rules as any LLM.
  • The output is a string, not structured data. You're parsing text for answers, so phrase questions to get parseable answers ("answer with a single word") when you're automating.
  • 3B is 3B. Expect it to nail obvious things and occasionally hallucinate fine detail, like any small VLM.

This is the node you don't appreciate until you need a caption in the middle of a workflow - then it's the only node that fits. It's quiet, cheap, and exactly as good as the question you ask it.

CategoryRunware/Text/runware

Inputs (2)

NameTypeDefaultDescription
imageIMAGE
promptoptSTRINGInstructions or questions to guide the image analysis.

Outputs (1)

NameTypeDescription
textSTRING