Feature Overview

Batch Processing

Resizer is able to process a large number of image files without user interaction (once the settings are determined). Any two folders on the hard drive can be assigned as the source and destination folders and all images that are of the supported format (determined by their extensions, i.e. jpeg, png, tiff, etc., will be processed).


Files which are not supported will not throw an error, they will simply not be processed. A notification is given when there are unsupported files.

Most major image formats are supported for both input and output.


A rotation angle can be specified and all images in the folder will be rotated by the specified amount. This feature is intended primarily for 90, 180 and 270 degrees, but any angle can be specified. Processing of angles other than the above, however, is not optimised and the resulting quality of the images may not be adequate.


Images rotated by an angle other than 90, 180 or 270 have their ‘additional’ spaces filled in a colour depending on format, usually black.


Images can be cropped in either of two ways:

  • By specifying a percentage of the original size
  • By specifying a specific pixel height and width


In all cases of cropping the centre of the image is retained (i.e. though width and height can be specified independently, cropping is symmetrical in the sense that the same amount is cut off from either side in each case). If the cropped image is to be larger than the original, an error is thrown.


Use cropping if you do not want any form of distortion but do not mind having some parts of the periphery of the picture removed.


Images can be squeezed or expanded in either of two ways:

  • By specifying a percentage of the original size
  • By specifying a specific pixel height and width

Since any squeezing or expanding will distort the image, a choice of four algorithms are offered as below.

Resizing Algorithms

Resizer offers the following algorithms within the Expand/Squeeze option:

  • Nearest Neighbour
  • Bilinear
  • Bicubic
  • AntiAlias/Lanczos


There are numerous limitations to Resizer’s scope, but particularly noteworthy are the following:

  • Resizer is not intended for very large files and will generally not handle these well on older computers without adequate memory.
  • It cannot process multi-page images such as those sometimes found in the gif or tiff formats. The only exception to this is pdfs which are output as individual files with page numbers as suffixes.
  • It also cannot read/process all variants of certain file formats.
  • See also the list of known issues Known Issues..

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