Image Save Simple Jpg

Image Save Simple Jpg (imageSaveSimple) from the zsq_prompt pack is a no-frills JPEG writer: feed it images, give it a filename prefix, and it drops JPGs into your ComfyUI output directory. The twist that makes it worth a page: a single only_preview toggle that decides whether the file lands in your real output folder or in a temp-only preview spot - so you can iterate a workflow without burying your good results under hundreds of junk files.

How it works

It's a thin subclass of the pack's SaveJpgImage (the "Image Save Jpg" node), which is itself a re-implementation of ComfyUI's core save logic - same get_save_image_path machinery, same batch numbering, JPEG quality 85. The only real difference is the toggle:

• only_preview = false (default) - saves to ComfyUI/output/ with your prefix, just like a normal save node.
• only_preview = true - writes to ComfyUI's temp directory with a random suffix and marks it temp. Nothing permanent lands in your output folder; the image shows up as a preview but doesn't accumulate in your "real" results.

It's an output node with no outputs - it terminates a branch.

Inputs and outputs that matter

• images - the IMAGE batch to save.
• filename_prefix - the prefix for filenames (default ComfyUI). Batch frames get numbered automatically.
• only_preview - the toggle that decides output vs. temp. That's the one input to actually think about.
• No outputs.

Where it fits

This is a "save while you work" node. The killer habit is setting only_preview to true during iteration - run 20 variations, keep your output folder clean, and flip the toggle to false only when you have a keeper you actually want in output/. For one-off exports where you always want the file on disk, the sibling SaveJpgImage is the same thing without the toggle; this one just adds the guardrail.

If you need PNG (lossless) or want the prompt/workflow embedded in the image metadata, this node isn't it - JPEG quality 85, no embedded workflow. Reach for ComfyUI's core Save Image for that.

Installing zsq_prompt

Shared pack install. ComfyUI Manager → search zsq_prompt → install, restart. Or:

cd ComfyUI/custom_nodes
git clone https://github.com/windfancy/zsq_prompt

Restart ComfyUI. The pack's requirements.txt is heavy - transformers, opencv-python, opencv-contrib-python, scikit-image, timm, onnx, ultralytics - overkill for a save node, but it's one shared install for the whole pack. If Manager flags "conflicting with zsq_prompt" on a workflow, that's dependency-overlap noise; only meaningful once the pack is actually installed. No model downloads needed.

Gotchas

• JPEG is lossy at quality 85. Fine for posting, wrong choice if you're chaining save→load→process loops.
• only_preview = true files are temp - don't go hunting for them in output/ afterward. That's the point.
• Batch frames are numbered with %batch_num% style suffixes, so multi-image batches save as separate files, not a grid.