Python bindings for the slimg image optimization library.
Supports macOS (Apple Silicon, Intel), Linux (x86_64, ARM64), and Windows (x86_64) -- native extensions are bundled in pre-built wheels.
import slimg
# Open an image file
image = slimg.open("photo.jpg")
print(f"{image.width}x{image.height} {image.format}")
# Convert to WebP
result = slimg.convert(image, format="webp", quality=80)
result.save("photo.webp")
# Optimize in the same format
result = slimg.optimize_file("photo.jpg", quality=75)
result.save("optimized.jpg")
# Resize by width (preserves aspect ratio)
resized = slimg.resize(image, width=800)
result = slimg.convert(resized, format="png")
result.save("thumbnail.png")
# Crop to aspect ratio (centre-anchored)
cropped = slimg.crop(image, aspect_ratio=(16, 9))
# Crop by pixel region
cropped = slimg.crop(image, region=(100, 50, 800, 600))
# Extend (pad) to aspect ratio with a fill colour
extended = slimg.extend(image, aspect_ratio=(1, 1), fill=(255, 255, 255))
# Extend with transparent padding (default)
extended = slimg.extend(image, aspect_ratio=(1, 1))
| Format |
Decode |
Encode |
Notes |
| JPEG |
Yes |
Yes |
MozJPEG encoder |
| PNG |
Yes |
Yes |
OxiPNG + Zopfli compression |
| WebP |
Yes |
Yes |
Lossy encoding via libwebp |
| AVIF |
Yes |
Yes |
ravif encoder; dav1d decoder |
| QOI |
Yes |
Yes |
Lossless, fast encode/decode |
| JPEG XL |
Yes |
Yes |
libjxl encoder/decoder |
| Function |
Description |
open(path) |
Decode an image file from disk |
decode(data) |
Decode image bytes (auto-detects format) |
convert(image, format, quality=80) |
Encode image in a target format |
resize(image, *, width/height/exact/fit/scale) |
Resize an image |
crop(image, *, region/aspect_ratio) |
Crop an image |
extend(image, *, aspect_ratio/size, fill) |
Pad an image canvas |
optimize(data, quality=80) |
Re-encode bytes to reduce file size |
optimize_file(path, quality=80) |
Read a file and re-encode |
| Type |
Description |
Format |
JPEG, PNG, WEBP, AVIF, JXL, QOI |
Image |
Decoded image with width, height, data, format |
Result |
Encoded output with data, format, and save(path) |
Resize |
Factory: width, height, exact, fit, scale |
Crop |
Factory: region, aspect_ratio |
Extend |
Factory: aspect_ratio, size |
SlimgError |
Error with subclasses: UnsupportedFormat, UnknownFormat, EncodingNotSupported, Decode, Encode, Resize, Crop, Extend, Io, Image |
| Platform |
Architecture |
Status |
| macOS |
Apple Silicon (aarch64) |
Supported |
| macOS |
Intel (x86_64) |
Supported |
| Linux |
x86_64 |
Supported |
| Linux |
ARM64 (aarch64) |
Supported |
| Windows |
x86_64 |
Supported |
MIT
