Comfyui-Image-Concat - a powerful image concatenation tool

✨ Core Features (Latest Update: Auto Horizontal Centering + Optional Vertical Centering)

This node is a powerful image concatenation tool for ComfyUI, with True Alpha Channel Support and Multiple Image-block Fill Modes:

I. Key Capabilities

1. Multiple Image-block Fill Modes (Image resizing mode for each block)

• 1.smaller value filler: Fill the block with the smaller value of the origin image's long side and the block's width (maintains aspect ratio)
• 2.Stretches image to fill: Stretches image to fill block (may distort aspect ratio)
• 3.zoom Long side(recommend): zoom long side of origin image to block width (maintains aspect ratio), then fill the block
• 4.crop square by short side: Crops square by short side of origin image(maintains aspect ratio), then zoom it to fill the block fully

2. Flexible Block Start Position Control:

• start_from margin: Blocks start directly at page margin (top/left aligned)
• start_from margin + spacing: Blocks start with extra spacing (top aligned)
• start_from margin + spacing(vertical centering): Auto vertical centering + horizontal centering

3. Optional Vertical Centering: Enabled via start_from margin + spacing(vertical centering) option

4. Multiple Background Styles: Light (white) / Dark (black) / Transparent (alpha channel)

5. Custom Border Styles: Block/Page borders: Rectangle / Rounded (10/20/30 radius) Border line styles: Solid / Dashed / Dotted / Dash-dot (fixed dashed line rendering bugs)

6. True 4-Channel Alpha Transparency: Export PNGs with full RGBA support (transparent background for margins/spacing/empty areas)

7. Save Individual Blocks: Export each image block as separate PNG (with alpha channel)

II. Input Parameters

III. 📤 Outputs

IV. Usage Examples

✅1. Basic usage

• (1) In the ComfyUI page, double-click mouse to search for "concat", locate the Image Concatenate(QQ2540968810) node, and click it to insert it into the ComfyUI page, or drag the following image into the ComfyUI page ;

Note: the above image can be found in "custom_nodes\Comfyui-Image-Concat\images\image_concat3.png".

• (2) Input directory path of images into a1_image_dir ;
• (3) Connect b1_concat_images output port to image preview node or image save node;
• (4) Input other parameters or Switch dropdown box if necessary;
• (5) Run to the Image Concatenate(QQ2540968810) node to get concated image(s) in comfyui/out directory;

Note: You can get help information about this node by connecting output b6_tips port to preview any node.

✅2. other workflow example (list by a8_draw_mode)

• (1) small value filler

Set your input port as below, you'll see 4 (show by b2_page_count out port) concated images. If you set a13_save_blocks = true, you can get all block files which you see in concated images in 'comfyui/concat_blocks' directory(you can modify it by a14_blocks_save_dir input port).

Note: the above image can be found in "custom_nodes\Comfyui-Image-Concat\images\image_concat1.png". You can drag the it into the ComfyUI page to run this example workflow.

• (2) stretches image to fill

Set your input port as below, you'll get 1 (show by b2_page_count out port) concated picture file in 'comfyui/output' directory. If you set a15_background_style = "transparent(alpha channel)", you can get picture file with RGBA channel. So you can edit its background layer in PS. If you set a13_save_blocks = "true", you can get all block files which you see in concated picture in 'comfyui/concat_blocks' directory(you can modify it by a14_blocks_save_dir input port).

Note: the above image can be found in "custom_nodes\Comfyui-Image-Concat\images\image_concat2.png". You can drag the it into the ComfyUI page to run this example workflow.

• (3) crop square by short side

Set your input port as below, you'll get 2 (show by b2_page_count out port) concated picture files in 'comfyui/output' directory. You can adjust a3_aspect_ratio input port to get vertical concated image picture. If you want the spliced graphic blocks to be centered vertically, you should set a7_block_first_position = "start_from margin + spacing(vertical centering)". If you set a15_background_style = "transparent(alpha channel)", you can get picture file with RGBA channel. So you can edit its background layer in PS.

Note: the above image can be found in "custom_nodes\Comfyui-Image-Concat\images\image_concat4.png". You can drag the it into the ComfyUI page to run this example workflow. Clicking https://drive.google.com/file/d/1in6XwuYF-DbZA8zPcgrFiY4NU4y-r_zp/view?usp=drive_link or click https://pan.baidu.com/s/1fu2_7Z3oOLG_LrHBd1Mk0w?pwd=gpan to download our source image zip file. Unzip it to any folder, you will get 59 source image files.

V. Installation method

1. Manual Installation (Recommended)

   (1) cd Comfy\custom_nodes;

   (2) git clone https://github.com/shmbatom/Comfyui-Image-Concat.git ;

   (3) Restart the ComfyUI Service.

2. Installation via Manager

   (1) Search for "Comfyui-Image-Concat" in the ComfyUI Manager and install it into ComfyUI/custom_nodes directory;

   (2) Restart ComfyUI;

   (3) Find the node under Image Processing/concat→Image concatenate(QQ2540968810).

VI. Notes

1. All output images maintain alpha channel (PNG format recommended)
2. Saved block images include borders and alpha channel
3. Border color auto-adapts to background style (white on dark, black on light/transparent)
4. block group centering:

• Horizontal Centering: Automatically calculates X offset
• Vertical Centering (Optional) Only enabled when you set a7_block_first_position = "start_from margin + spacing(vertical centering)".

5. Maximum page size: 50000px (adjust max in INT parameters if needed)
6. Supported image formats: PNG, JPG, JPEG, BMP, GIF

VII. 💡 Tips

1. For best results with transparent background: Use PNG format for input images
2. Zoom Long side (recommend) resize mode preserves image aspect ratio
3. Rounded borders with radius 20 work best for block sizes > 500px
4. Enable "Save individual block images" for post-processing single blocks

VIII. Donation

If you think this tool is decent, you can donate a cup of coffee to me.