Borderize 1.0.2

borderize

A CLI tool for adding borders to photos. Designed for camera export workflows — point it at a folder or glob pattern and it writes bordered copies alongside the originals.

Border styles

Uniform — equal white border on all four sides. Good for a clean, gallery-print look.

Polaroid — thinner border on the top and sides, thick border on the bottom. Mimics the classic Polaroid print proportions.

Aspect — pads the image, centered, to a target aspect ratio (default 1:1) with at least the --size margin around it. Good for square or 4:5 social-media framing.

Installation

Requires the .NET 10 SDK.

From NuGet (recommended)

Install the published tool from nuget.org:

dotnet tool install --global Borderize

Update to the latest version later with:

dotnet tool update --global Borderize

From source

To run a local build — for testing changes or contributing:

git clone <this repo>
cd borderize
dotnet pack -o ./nupkg -c Release
dotnet tool install --global --add-source ./nupkg borderize

PATH setup

If borderize isn't found after installing, add the .NET tools directory to your PATH (one-time setup):

cat << \EOF >> ~/.zprofile
# Add .NET Core SDK tools
export PATH="$PATH:/Users/$USER/.dotnet/tools"
EOF

Restart your terminal, or run zsh -l to apply immediately.

Usage

borderize <input> [options]

<input> can be:

• A single file: ./IMG_1234.jpg
• A folder: ./export/2024-japan/ — processes all supported images inside
• A glob pattern: "./photos/*.jpg" — quote it to prevent shell expansion

Supported formats: .jpg, .jpeg, .png, .webp

Output is written alongside the original with a suffix appended to the filename. The original is never modified.

IMG_0042.jpg  →  IMG_0042-border.jpg

Examples

# Polaroid border on a single photo
borderize ./IMG_1234.jpg --style polaroid

# Uniform border on every photo in a folder
borderize ./export/2024-japan/ --style uniform

# Glob — only select files by pattern
borderize "./export/*.jpg" --style polaroid --suffix -x-border

# Preview what would be processed without writing anything
borderize ./photos/ --dry-run

# Custom pixel border size with a hex color
borderize ./photos/ --size 80 --color "#F5F0EB"

# Recurse into subfolders
borderize ./library/ --recursive --style polaroid

# Square pad for social media (1:1 by default)
borderize ./photos/ --style aspect

# 4:5 portrait pad
borderize ./photos/ --style aspect --aspect 4:5

# Throttle concurrency on a large batch
borderize ./export/ --recursive --parallel 4

Options

Notes

• Files whose names already end with the configured suffix are skipped automatically, so re-running on a folder won't double-border your outputs.
• PNG output is lossless; --quality only applies to JPEG and WebP.
• Border size as a percentage scales with the image, so the same command works on both high-resolution camera files and smaller exports.