im-local

Self-hosted image transformations over HTTP: resize, crop around faces and features, colour work, compositing, and background removal. Output formats are negotiated per client. Everything below is rendered live by this server.

Source

source image
drop an image here, or

Client capabilities

The service picks an output format from what the client accepts. These switches change the Accept header used for every request on this page, so you can see what a different device would get.

Playground

result

        
        
      

    

  





Request



  
GET /process?url=<source>&im=<transformations>[&out=auto][&prefer=avif,webp,jxl][&quality=90]

  

    
parameterdescription

    
urlAbsolute http or https URL of the pristine image. Hosts are restricted by configuration.

    
imTransformation chain, separated by ;, applied left to right.

    
imopAlias for im.

    
width, heightShortcut for a resize.

    
outjpeg, png, webp, avif, jxl are encoded as asked. auto negotiates. Omitted keeps the source format.

    
preferPreference order for negotiation, for example avif,webp,jxl. The first format the client accepts wins.

    
quality1 to 100, default 90. Mapped per encoder.

    
nocacheRecompute instead of reading the cache.

  

  
Derivatives are cached in /app/cache for 1h30m0s, keyed by source,
  transformation chain, format, and quality. Responses carry ETag, Cache-Control and
  Vary: Accept; the X-Cache chip on each card shows whether it came from disk. A negotiated
  format switches to PNG rather than dropping an alpha channel.






Output format and encoding



  
  

    
Source format

    
No out parameter keeps the format of the pristine image.

    
Source format

    

    
(no transformation)

    

      
      
      
      
    

  

  
  

    
WebP

    
Widely supported, carries an alpha channel.

    
WebP

    

    
out=webp

    

      
      
      
      
    

  

  
  

    
AVIF

    
Usually the smallest of the three at the same quality, and the slowest to encode.

    
AVIF

    

    
out=avif

    

      
      
      
      
    

  

  
  

    
JPEG XL

    
Supported by few browsers today; useful when the client is known.

    
JPEG XL

    

    
out=jxl

    

      
      
      
      
    

  

  
  

    
Negotiated

    
out=auto picks the first format the client accepts, from avif, webp, jxl.

    
Negotiated

    

    
out=auto

    

      
      
      
      
    

  

  
  

    
Preference order

    
prefer sets that order explicitly, here webp before avif.

    
Preference order

    

    
out=auto&prefer=webp,avif,jxl

    

      
      
      
      
    

  

  
  

    
Quality

    
Quality is mapped per encoder; 1 to 100, default 90.

    
Quality

    

    
quality=20

    

      
      
      
      
    

  

  
  

    
Transparency is kept

    
A negotiated format switches to PNG when a transformation adds an alpha channel.

    
Transparency is kept

    

    
im=Resize,width=300;Rotate,degrees=15

    

      
      
      
      
    

  

  




Resizing and scaling



  
  

    
Resize

    
Resize=(width,height) resizes to exact dimensions.

    
Resize

    

    
im=Resize=(300,150)

    

      
      
      
      
    

  

  
  

    
Resize, one dimension

    
Omit a dimension to keep the aspect ratio.

    
Resize, one dimension

    

    
im=Resize,width=220

    

      
      
      
      
    

  

  
  

    
Scale

    
Scale by a factor of the current size.

    
Scale

    

    
im=Scale,width=0.25,height=0.25

    

      
      
      
      
    

  

  
  

    
Fit and Fill

    
Fit inside the box and fill the rest with a blurred copy.

    
Fit and Fill

    

    
im=FitAndFill=(320,320)

    

      
      
      
      
    

  

  




Cropping



  
  

    
Crop

    
Crop a rectangle, optionally with a gravity.

    
Crop

    

    
im=Crop,rect=(0,0,300,300),gravity=Center

    

      
      
      
      
    

  

  
  

    
Crop with expansion

    
allowExpansion pads with transparency instead of clamping.

    
Crop with expansion

    

    
im=Crop,size=(1200,300),allowExpansion&out=png

    

      
      
      
      
    

  

  
  

    
Aspect Crop

    
Crop to an aspect ratio; xPosition/yPosition pick the kept region.

    
Aspect Crop

    

    
im=AspectCrop=(16,9),xPosition=.5,yPosition=.3

    

      
      
      
      
    

  

  
  

    
Aspect Crop, expanded

    
allowExpansion adds transparent pixels instead of cropping.

    
Aspect Crop, expanded

    

    
im=AspectCrop=(1,1),allowExpansion&out=png

    

      
      
      
      
    

  

  
  

    
Relative Crop

    
Shrink or expand each edge relative to the current size.

    
Relative Crop

    

    
im=RelativeCrop,north=100,south=100,east=50,west=50

    

      
      
      
      
    

  

  
  

    
Region of Interest Crop

    
Crop around a focal point.

    
Region of Interest Crop

    

    
im=RegionOfInterestCrop=(300,300),regionOfInterest=(300,220)

    

      
      
      
      
    

  

  
  

    
Feature Crop

    
Crop around the most prominent features.

    
Feature Crop

    

    
im=FeatureCrop,size=(300,300)

    

      
      
      
      
    

  

  
  

    
Face Crop

    
Crop around detected faces.

    
Face Crop

    

    
im=FaceCrop,width=300,height=300

    

      
      
      
      
    

  

  
  

    
Smart Crop

    
Faces when present, features otherwise.

    
Smart Crop

    

    
im=SmartCrop,size=(300,300)

    

      
      
      
      
    

  

  
  

    
Trim

    
Trim uniform edges.

    
Trim

    

    
im=Trim,tolerance=0.05;Resize,width=300

    

      
      
      
      
    

  

  




Orientation and distortion



  
  

    
Mirror

    
Flip horizontally or vertically.

    
Mirror

    

    
im=Mirror,horizontal;Resize,width=300

    

      
      
      
      
    

  

  
  

    
Rotate

    
Positive degrees rotate clockwise; the canvas grows.

    
Rotate

    

    
im=Resize,width=300;Rotate,degrees=13&out=png

    

      
      
      
      
    

  

  
  

    
Shear

    
Slant into a parallelogram.

    
Shear

    

    
im=Resize,width=300;Shear,x=0.3&out=png

    

      
      
      
      
    

  

  
  

    
Goop

    
Distort the image; chaos ranges from 0 to 1.

    
Goop

    

    
im=Resize,width=300;Goop,chaos=1

    

      
      
      
      
    

  

  




Color



  
  

    
Grayscale

    
Render in shades of gray.

    
Grayscale

    

    
im=Resize,width=300;Grayscale

    

      
      
      
      
    

  

  
  

    
Contrast

    
Values above 1 increase contrast.

    
Contrast

    

    
im=Resize,width=300;Contrast,contrast=1.6

    

      
      
      
      
    

  

  
  

    
HSL

    
Hue rotation plus saturation and lightness multipliers.

    
HSL

    

    
im=Resize,width=300;HSL,hue=0.2,saturation=1.6,lightness=1.1

    

      
      
      
      
    

  

  
  

    
HSV

    
Same idea using value instead of lightness.

    
HSV

    

    
im=Resize,width=300;HSV,hue=0.5,saturation=2,value=1

    

      
      
      
      
    

  

  
  

    
Mono Hue

    
Force every hue to one value, in degrees.

    
Mono Hue

    

    
im=Resize,width=300;MonoHue,hue=210

    

      
      
      
      
    

  

  
  

    
Max Colors

    
Reduce the palette to shrink the file.

    
Max Colors

    

    
im=Resize,width=300;MaxColors,colors=8

    

      
      
      
      
    

  

  
  

    
Background Color

    
Fill transparency with a color.

    
Background Color

    

    
im=Resize,width=300;Rotate,degrees=13;BackgroundColor,color=00ff00

    

      
      
      
      
    

  

  




Transparency



  
  

    
Opacity

    
Multiplier on the current opacity.

    
Opacity

    

    
im=Resize,width=300;Opacity=0.35&out=png

    

      
      
      
      
    

  

  
  

    
Chroma Key

    
Remove a hue range, green by default.

    
Chroma Key

    

    
im=Resize,width=300;ChromaKey,hue=40,hueTolerance=0.15&out=png

    

      
      
      
      
    

  

  
  

    
Remove Color

    
Remove one color with tolerance and feathering.

    
Remove Color

    

    
im=Resize,width=300;RemoveColor,color=e8e2d8,tolerance=0.08,feather=0.05&out=png

    

      
      
      
      
    

  

  




Background removal



  
  

    
Background Remove

    
Cut the subject out with a locally executed segmentation model, no hosted service involved.

    
Background Remove

    

    
im=Resize,width=320;BackgroundRemove,fallback=color&out=png

    

      
      
      
      
    

  

  
  

    
Hard edges

    
threshold turns the soft mask into a firmer cut-out; feather controls the ramp.

    
Hard edges

    

    
im=Resize,width=320;BackgroundRemove,threshold=0.6,feather=0.05,fallback=color&out=png

    

      
      
      
      
    

  

  
  

    
Replace the background

    
Chain BackgroundColor to drop the subject onto a flat colour.

    
Replace the background

    

    
im=Resize,width=320;BackgroundRemove,fallback=color;BackgroundColor,color=0b7285

    

      
      
      
      
    

  

  




Background removal without a model



  
  

    
Colour method

    
method=color needs no model at all. It suits clean backdrops like this one, not busy scenes.

    
Colour method

    

    
im=Resize,width=320;BackgroundRemove,method=color&out=png

    

      
      
      
      
    

  

  
  

    
Colour method, replaced

    
The same cut-out dropped onto a flat colour.

    
Colour method, replaced

    

    
im=Resize,width=320;BackgroundRemove,method=color;BackgroundColor,color=0b7285

    

      
      
      
      
    

  

  
  

    
Remove Color

    
Remove one specific colour instead of learning it from the border.

    
Remove Color

    

    
im=Resize,width=320;RemoveColor,color=eceae4,tolerance=0.1,feather=0.05&out=png

    

      
      
      
      
    

  

  




Detail



  
  

    
Blur

    
Gaussian blur; higher is blurrier.

    
Blur

    

    
im=Resize,width=300;Blur=4

    

      
      
      
      
    

  

  
  

    
Unsharp Mask

    
Sharpen edges and detail.

    
Unsharp Mask

    

    
im=Resize,width=300;UnsharpMask,gain=3

    

      
      
      
      
    

  

  




Compositing



  
  

    
Composite

    
Overlay another image, for example a watermark.

    
Composite

    

    
im=Resize,width=300;Composite,image=(url={sample}),gravity=SouthEast,scale=0.1,opacity=0.7

    

      
      
      
      
    

  

  
  

    
Composite, underlay

    
placement=under puts the source image on top.

    
Composite, underlay

    

    
im=Resize,width=300;Rotate,degrees=10;Composite,image=(url={sample}),placement=under,gravity=Center,scale=0.4

    

      
      
      
      
    

  

  
  

    
Append

    
Place another image beside the source.

    
Append

    

    
im=Resize,width=200;Append,image=(url={sample}),gravity=East

    

      
      
      
      
    

  

  




Conditions



  
  

    
If Dimension

    
Branch on the current width or height.

    
If Dimension

    

    
im=IfDimension,value=500,dimension=width,greaterThan=$(Resize=(300,200)),lessThan=$(Grayscale)

    

      
      
      
      
    

  

  
  

    
If Orientation

    
Branch on portrait, landscape, or square.

    
If Orientation

    

    
im=IfOrientation,landscape=$(Resize=(300,169)),portrait=$(Resize=(169,300)),square=$(Resize=(300,300))

    

      
      
      
      
    

  

  




Chaining and legacy parameters



  
  

    
Chained transformations

    
Transformations run left to right, separated by semicolons.

    
Chained transformations

    

    
im=AspectCrop=(1,1);Resize,width=300;Grayscale;Blur=2

    

      
      
      
      
    

  

  
  

    
Legacy imop

    
The imop parameter is an alias for im.

    
Legacy imop

    

    
imop=Resize,width=300,height=150

    

      
      
      
      
    

  

  
  

    
Legacy width and height

    
Bare width and height still resize.

    
Legacy width and height

    

    
width=300&height=150