Actions and Settings Explained

Standard Actions

Standard actions are the basic actions that you are likely to use most often in Pixel Grinder.

Add Watermark

The add watermark action allows you to overlay a watermark image that you have created in another graphics package over every image that is processed. You must specify the image to overlay with the watermark image option for this action to operate.

The anchor point specifies which corner of the original image the watermark image is over-layed in relation to. The offset values then determine how far away from this corner your image is placed, allowing you to accurately place your watermark on your images. The opacity slider allows you to apply a watermark image with a given amount of transparency so that the watermark doesn’t obscure the underlying image. With opacity 100, the watermark is exactly the same as the source image, with opacity 0 the watermark is invisible.

Move Source Image

If you wish to have your source image moved as it is being processed then you can select a different folder on your drive to move an image to as part of the processing sequence. This allows you to move an image out of your input directory so that the next time you hit ‘Start’, only new images will be processed from any input folders specified. Please note that moving images that were added as ‘input files’ will remove them from the list of input files after processing is complete.


The resize action will resize your image using one of four methods;

  • Resize to Width: All images will be resized proportionately (maintaining the original aspect ratio) so that all of your images have the specified width.
  • Resize to Height: All images will be resized proportionately (maintaining the original aspect ratio) so that all of your images have the specified height.
  • Fit to Box: All images will be resized proportionately (maintaining the original aspect ratio) so that the resulting image will fit inside the specified sized box.
  • Force to Box (Distort): All images will be resized exactly to the specified size, which will distort the aspect ratio of your original image if necessary.

The Allow Enlargement option determines whether this resize action is allowed to resize images to be larger than the original source image, which will cause a loss in quality of the original image.


The save action is used to save your image after a sequence of actions has been performed on it. You can have multiple save operations in a single queue, for instance, if you want to resize your images once, save them and then resize them again to thumbnail size and save them a second time.

The output folder specifies the location to which this action will save the processed images. The file name option allows you to describe how you would like the output files to be named. The following special tags can be used in this text to give the images a sensible name.

  • {OriginalName} is replaced by the original file name (without the file format extension).
  • {FileNumber} is replaced by the number that was given to this image in the processing queue – for instance, for the 7th image processed this would be replaced by the number 7.

Pixel Grinder currently supports JPG and PNG file formats as outputs for the format option. The compression setting only applies to images that are saved as JPG files. Please note that PNG files are ‘PNG-24′ files which retain full image transparency.

If the for retina display? option is checked, then the save action will save the original image as normal but with the ‘@2x’ suffix, and then it will save a half-sized image with the regular file name. This option is for iOS developers.

If the allow overwrite option is checked, then the save action will overwrite any images that already exist in the output directory. If this option is unchecked, Pixel Grinder will append a number until a safe, unused filename is found.

Blur / Sharpen Actions

These actions are used to add either a blur effect to your images or to sharpen an image. It can be a good idea to apply an Unsharp Mask action after you have resized an image to enhance the shapes that have been reduced in the image. This category also contains a noise reduction filter to remove grain and dirt from noisy photos.

Box Blur, Disc Blur, Gaussian Blur

The blur filters all apply a similar effect to your image. They will blur each pixel in your image based on the values of nearby pixels. The blur options all have a blur radius parameter which will affect how intense the blur effect is on your image.


The sharpen filter is a basic sharpening filter that will help to enhance the edges and boundaries in your image. The sharpen action only has one parameter, sharpness which affects how intense the sharpening effect should be on your image.

Unsharp Mask

The unsharp mask filter is an advanced image enhancing filter that can help to improve your image quality after resizing large images down to a much smaller size. Unsharp Mask helps to enhance the edges in your image, and will modify colours in your image to improve this effect. You can select the radius and intensity of this effect which will affect how prevalent the Unsharp Mask effect should be.

Noise Reduction

The noise reduction filter aims to remove grain and reduce the noise effect that you often see in low light conditions. The noise reduction filter first attempts to strip the noise from the image and you can set how much noise is stripped by setting the noise level parameter. This filter than attempts to repair any damage done by removing texture from the image when removing noise by applying a sharpening effect on the image. You can set the intensity of this effect by altering the sharpness setting.

Colour Adjustment Actions

These actions all affect the underlying colours that appear in your image, and can be used to enhance images that have been under-exposed. You can also apply a Sepia effect to your image for example if you would like to apply a specific effect to a series of photographs for instance.

Adjust Colours

This action lets you modify some of the core features of the colours in the image, such as the saturation, brightness and contrast. The settings for this action are as follows;

Saturation: the image saturation determines how intense the colours of the image should be. The default setting of 1 will not alter the colours. Using a setting of 0 will remove all colour information from the image, leaving a grayscale image and using a setting of 2 will greatly intensify the colour information in your image.

Brightness: affects the overall brightness of each pixel in your image. The default setting of 0 will leave each pixel unaffected. Using a negative setting will linearly reduce each colour value of each pixel, making your image darker overall. Using a setting above 0 will push each pixels colour values closer to white.

Contrast: affects the overall difference between the lighter and darker areas of your image. The default value of 1 will leave your image unaffected. Using a value above 1 will brighten light parts of your image more and darken the darker parts of your image. Using a negative setting allows you to reduce the contrast in an image.

Adjust Exposure

The adjust exposure action attempts to fix images that were taken with a camera that applied too much, or too little exposure for an image. The exposure change setting will brighten and/or darken the image accordingly in an attempt to reproduce the effect of the camera having using a shorter or longer exposure time for the original image.

Adjust Gamma

The adjust gamma action applies an effect to the colour curves of an image and can be useful for recovering information that is lost in excessively dark images. The gamma change setting determines how much the gamma curve of the image should be modified, where the value 1 has no effect on the original image. Using a value above 1 will darken the image and make it more intense, where using a value less than one can help to recover texture in darker areas of the image without having too much of an effect on the lighter parts of the image (as with Brightness / Contrast).

Adjust Hue

The adjust hue action allows you to rotate the hue of each coloured pixel in an image. You can think of this as moving all of the colours in your image around a colour wheel by a specified amount (in radians). This effect is most useful for digital artwork where the majority of the work lies within a specific band of colour. For instance, you could use this action to re-colour a collection of sprites in for a game.

The angle parameter specifies how much the hue of each pixel should be rotated, in radians.

Grayscale Image

This simple action has no options and simply discards the colour information from each pixel and uses the saturation and brightness to generate a grayscale representation of the original image.

Invert Image

This action simply inverts the amount of each colour that exists in each pixel of your image. In this sense, blacks become white and blues become yellow, etc. This action has no options, it simply flips the colour value of each colour for each pixel in your image.

Sepia Tone

This action applies a sepia effect to your image to produce the effect of an old photograph. This essentially discards the colour information, much like with a grayscale image, and then applies a brown colour to the pixels to produce the effect of an old photograph.

The intensity of this effect determines how much of the original image colour to leave in effect. With an intensity of 0 this action has no effect, and with an intensity of 1 all of the original colour information is discarded in favour of the sepia effect.

Special Effects Actions

These actions all apply a special effect to your image which may be useful in specific circumstances, for instance, when preparing images for uploading to a website.


This action adds a bloom lighting effect to your image, producing a softness around the lighter areas of your image, as though you are viewing the image after being in the dark.

The radius setting determines how big the effect should be around the lighter parts of your image, while the intensity setting determines how visible the effect should be within the effected pixels.


The crystallize action applies a stained glass window effect to your image which is similar to pixellating your image but without the exact square boundaries around each pixel.

The radius setting determines how large the resulting panels of colour are.

Edge Detection

The edge detection action will reduce much of your image to a black colour and will highlight any boundaries between distinct areas of colour within your image. This has the effect of producing a neon outline type image from your original source.

The intensity of this action will determine how bright the resulting edges appear on the final image.

Edge Work

Similar in many ways to the edge detection filter, this filter will produce an effect as though your image had been cut into a piece of wood work. The resulting grayscale image will strongly highlight the boundaries of your original image. This effectiveness of this filter is highly dependent of the source image. The radius setting effectively determines the size of the tool that would have been used to create the image.


This filter is effectively opposite to the bloom filter, and reduces the highlights of your image based on the values of nearby pixels.

The radius setting determines how big the effect should be around the lighter parts of your image, while the intensity setting determines how visible the effect should be within the effected pixels.


The pixellate filter breaks your image down into discrete blocks of colour that represent an average of the colours that were present in the source pixels that are being affected. This turns your artwork into a block ‘retro’ image.

The scale option represents how big the resulting blocks of colour should be.