> For the complete documentation index, see [llms.txt](https://docs.augelab.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.augelab.com/function-blocks/blocks-reference/image-transformations/operations/collage-images.md).

# Collage Images

This function block creates a single collage image from multiple input images. If a matching flag list (OK/NOK) is provided, the collage adds colored borders to each tile to indicate status.

## 📥 Inputs <a href="#inputs" id="inputs"></a>

* `Image List` A list of images to be combined into the collage (can be images of different sizes).
* `Flag List` Optional list of boolean or status flags (OK/NOK) matching each image in the `Image List`. When provided, tiles show a border color indicating the flag state.

## 📤 Outputs <a href="#outputs" id="outputs"></a>

* `Collaged Image` The resulting combined image created from the input list.

## 🕹️ Controls <a href="#controls" id="controls"></a>

* `Select Image Size (Pixel)` Use this slider to set the tile size used in the collage layout. Larger values produce bigger tiles and a larger final collage image.

## 🎨 Features <a href="#features" id="features"></a>

* Easy merging of many images into a single preview image suitable for reports, dashboards, or quick inspection.
* Optional flagging support to visually mark each tile as OK or NOK using borders.
* Adjustable tile size so you can balance detail and final collage dimensions.
* Accepts mixed image sources (camera frames, processed crops, saved images).

## ⚙️ Running mechanism <a href="#how-it-works" id="how-it-works"></a>

When executed, the block reads the provided `Image List` and optionally the `Flag List`. It resizes or tiles images according to the chosen `Select Image Size (Pixel)` and lays them out into a grid. If flags are present and match the image count, each tile receives a border color that indicates its OK/NOK state. The final combined image is emitted from the `Collaged Image` output.

## 📝 Usage instructions <a href="#usage" id="usage"></a>

1. Prepare the images you want combined and provide them to the `Image List` input.
2. Optionally provide a corresponding `Flag List` of equal length to add status borders.
3. Adjust `Select Image Size (Pixel)` to change tile size for readability or compactness.
4. Connect the `Collaged Image` output to a display or save block to inspect or store the result.

## 💡 Tips and Tricks <a href="#tips-and-tricks" id="tips-and-tricks"></a>

* Normalize input sizes for better-looking collages: use `Image Resize` or `Image Resizer` before feeding images into `Image List`.
* If you want to collect multiple cropped regions from a single source, use `Image ROI Select Multi` to build your `Image List`.
* Generate flags automatically by combining detection blocks such as `Mask Detection`, `Object Detection`, or `Object Detection - Custom`. Use detection results (OK/NOK logic) to build the `Flag List` for visual inspection.
* Preview the final collage interactively by connecting the output to `Show Image`.
* Save collages automatically using `Multi Image Write` or log them with `Image Logger` for traceability.
* When using many images, reduce `Select Image Size (Pixel)` to keep the final collage within display or file size limits.

## 🛠️ Troubleshooting <a href="#troubleshooting" id="troubleshooting"></a>

* If borders appear missing or incorrect, confirm the `Flag List` length equals the `Image List` length.
* If images look stretched or cropped unexpectedly, add an `Image Resize` step to standardize aspect ratios before creating the collage.
* If the collage is too large for display or saving, lower the `Select Image Size (Pixel)` value.