To adjust the contrast, you can use the contrast filter and set the desired adjustment value.

contrast=X

Examples

Filters allow you to modify images on-the-fly by applying different effects.

Available filters

Combining filters

To use more than one filter, you can either use separate parameters or concatenate them with commas into the f parameter:

To create a color overlay by using colorize=X[,Y], where X is the color of the overlay (hex value or color name) and Y is the opacity (Y=0..1, default 0.5).

colorize=X[,Y] | colourise=X[,Y]

To adjust the brightness, you can use the bright filter and set the desired adjustment value.

bright=X

Examples

Applies a pixelation effect to an image. You can set the desired block size in pixels. If the image is resized the filter is applied after resizing.

pixelate=X | pixellate=X

Examples

Applies Gaussian blur to the image. The parameter value (X) is the kernel size of the filter in pixels.

blur=X

Examples

To adjust the color saturation, you can use the saturate=X filter and set the desired adjustment value (X= -100..100). Negative values will decrease color saturation while positive ones will increase it.

saturate=X

Examples

Desaturate

Using saturate=-100 will remove all color information and convert the image to grayscale.

Examples

Sharpening is a powerful tool to emphasise texture and details, especially on smaller images, e.g. thumbnails. Filerobot can apply an unsharp mask filter which will make your image look sharper. You can specify the filter radius (X) in pixels.

sharp=X

Examples