The application I am writing depends on relatively consistent output from the resample function. I need to be able to, as portably as possible. resize. -resize x+20+30 (like the -scale and -sample examples below) converts an input to an output image which has the pixel dimensions of x Hello, I am trying to reduce the resolution of images to 72×72 using convert – resample 72×72 when I do this the image size does get reduced.

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See —resize for details about the geometry specification.

Problems with resampling to change resolution – ImageMagick

The density option is an attribute and does not alter the underlying raster image. Liquid Rescaling, is currently a highly experimental operation added for IM v6. Specify the amount of tinting as a percentage.

Without antialiasing, you can avoid increasing the unique colors in an image, draw fixed width lines, or resampe the rendering speed. This option applies a special effect to the image, similar to the effect achieved in a photo darkroom by sepia toning. The replace method changes the matte value of any pixel that matches the color of the target pixel.

My problem is that after resampling a bunch of images iimagemagick use for the web, some of them resample, say that their resolution is now 72×72, and they appear the same size on a website. Consider the target pixel as that specified by your coordinate. Use this option to affect the the color management operation of an image see —profile. Thus the final resolution of the image in combination with the number of pixels will produce the resolution resamplle that in combination matches imagemagici density needed for that hardware.


Use identify -verbose to find out what profiles are in the image file. If no density attribute has been set IM will assume it has a default density of 72dpi. Coordinates are integers separated by an optional comma. The —gravity option is also used in concert with the —geometry option and other options imagejagick take geometry as a parameter, such as the —crop option. This is the number of bits in a color sample within a pixel.

IM has always tried to provide options to give you the maximum scope of control in image resizing. Note that resizing distorting an image with non-linear color channels in RGB colorspace, can lead to slightly different results in each color channel.


The color is specified using the format described under the —fill option. A “Minify ” function is also often available in API’s that halve the size of images but is just a wrapper resampel resize. This will create a 3-D effect.

There are hundreds of posiblilties, styles, and techniques, and even resize experts are consantally trying to find new and different ways of changing an images size. RoundRectangle has the upper left and lower right coordinates and the width and height of the corners. Sigmoidal transform essentually generates a special DIY non-linear colorspace, that builds on the previous results that was obtained when using a non-linear perceptual colorspace sRGB.

For unfilled shapes, use —fill none. If I need to make various size large picture thumbnail with fixed aspect ratio cropping needed — what’s my best choice? That is, the image is expanded or contracted to fit the width and height value while maintaining the aspect ratio of the image. This is a convenience option for annotating your image with text.


If this profile exists in the image, then Photoshop will continue to treat the image using its former resolution, ignoring the image resolution specified in the standard file header. You can include the image filename, type, width, height, or other image attribute by embedding special format characters listed under the —format option. Specify the width of the region to be removed from both sides of the image and the height of the regions to be removed from top and bottom.

Follow the text coordinates with a string. Similarly, if only the height is specified e.

Resample Image to Size in Pixels With ImageMagick

Multiplies or screens the desample, dependent on the destination color. Follow the pixel coordinate with a method see the color primitive for a description of methods.

Empty triangles left over from rotating the image are filled with the color defined as background.

Use —page xfor example, to center the image within the page. Create an image such that any pixel sample that is equal to, or exceeds the threshold, is reassigned the maximum intensity otherwise the minimum intensity. The principal function of noise peak elimination filter is to smooth the objects within an image without losing edge information and without creating undesired structures.

This option compares each image with the next in a sequence and returns the maximum bounding region of any pixel differences it discovers.