What is it?

DBP (David's Batch Processor) is a simple batch processing plugin for the Gimp - it allows the user to automatically perform operations (such as resize) on a collection of image files. Its main advantage is that the user does not have to learn a scripting language. Like the Gimp itself, DBP relies on a graphical interface. The user creates a list of images, and sets up the processing required for each image. The results of the current settings can be displayed. Once the required sequence of operations has been set up, DBP performs the same processing on each image in turn. The images can be colour corrected, resized, cropped, and sharpened, then renamed and saved to a different file in a specified image format. All the steps (except loading and saving the image!) are optional; so the simplest use of DBP is just to convert a number of image files from one format to another.

Note that DBP is intended for RGB, not indexed images. Trying to process an indexed image will probably just cause an error, and DBP will halt. Also, DBP will not overwrite the original image (in fact, it should not overwrite any file) - images must at least be either renamed (possibly by changing the image format) or moved to a different directory.

Where do I get it?

DBP is licensed under the GPL. The latest version is 1.1.9. It has been updated to work with recent Gimp 2.6 versions, but will probably work with earlier versions. The source is available at:
If you have problems with this version, earlier versions are still around at:
http://www.ozemail.com.au/~hodsond/dbpSrc-1-1-8.tgz and:
There is no configure file, use make install to build and install in your local gimp plugins directory. You will need g++ and the gimp development packages for the appropriate Gimp version - if you can compile C++ and can build any other Gimp plugin, you should have no problems. The Makefiles are very primitive and can be edited directly if needed.

Windows Users

I don't have the facilities to create Windows versions myself, but other people have done so and sent them to me. Rodrigo Flores kindly provided me with a Windows binary version of 1.1.8 which is available at:
and Michael Schumacher provided me with an earlier version:
http://www.ozemail.com.au/~hodsond/dbp-1.1.3.zip Just download and unzip the file, and copy dbp.exe into your plugins folder - check Edit/Preferences/Folders/Plug-ins to find out where it should go.

How does it work?

Main window

From the Filters menu in the main Gimp window (or Xtns in earlier versions), select Batch Process... to bring up the DBP window. The top section lets you set up the processing steps; the bottom section starts and stops the processing, and shows its progress. Note that some of the controls are inactive; DBP disables controls which currently have no effect.

The processing steps are laid out on a series of pages, one for each step.
Hint: start at the Input page and set up each one in order.
Hint: use the Test button to see the effect of the processing.
ToDo: need to see which steps are enabled without having to go to their page.
ToDo: save and load processing settings.


DBP starts with the Input page open. The Input page is used to specify the images to process. The Add Files button raises a standard GTK+-2 file selector. Note that you can select multiple files, using shift-click to select a range of files, and control-click to select and deselect individual files. Note also that the input files can be in different image formats. (However, they should all have different names when the file extension is removed.)

The Open button adds the selected files to the input list and closes the file selector. The Add button adds the selected files to the list and clears the selection, but does not close the dialog, so that you can add files from other directories. Close simply closes the file selector without adding any more files. Once the file selector is closed, the file list can be edited by selecting one or more entries and using the Remove Files button to remove them, by using Clear List to clear the list completely. You can add more files by pressing Add Files to reopen the file selector.
Note: the file selector is modal, so you must close it before you can adjust any controls in the main window.
ToDo: save and load input lists.


The next pages control the processing. Each page starts with an Enable toggle, which turns on the image operation for that page and lets you set the controls. To see the effect of all the active operations (on the first image in the file list) at any time, press the Test button. The operations are applied to the images in the order shown on the pages.


If enabled, rotates the image through 90, 180, or 270 degrees.


If enabled, blurs the image.
Hint: uses Gauss IIR.


If enabled, adjusts brightness and contrast of the image, either through the Gimp Auto Levels function, or by the control settings. The image saturation can be adjusted, and the image can be converted to black and white (although the image Mode will still be RGB, not Grayscale).
Note: converting to black and white does not give the same result as reducing the saturation to zero.
ToDo: add gamma control.


If enabled, resizes the image. Resizing can be either relative to the input image size, or to an absolute target size. Fixing the aspect ratio of a relative resize locks the x and y sliders to the same value. There are four options for an absolute resize. Exact will change the aspect ratio of the image, if necessary, to fit the target size. Pad fits the resized image inside the target size, then pads it to fit. Inside creates the largest image which fits inside the target size, Outside the smallest which fits outside.
Hint: padding uses the Gimp's current background colour.
Hint: resize uses the Gimp's Interpolation Type settings.


If enabled, crops a region from the image.
Warning: The region must be contained within the image area.


If enabled, sharpens the image.
Hint: uses Unsharp Mask.


Sets the directory and file name to use when saving the processed image. Source Dir refers to the directory containing the original image. If another directory is chosen, the image will be saved there instead. The original file name can have a prefix or postfix added; its extension will be replaced by the appropriate extension for the image format chosen on the next page. An example of the renaming is shown (using an imaginary extension).
Hint: DBP will not overwrite an existing file. The output file must be renamed, have its extension changed, or be put into a different directory.
ToDo: add relative directory path.

Also includes a toggle to flatten the image before saving, which will mostly just remove the alpha channel. This doesn't really belong here, but I needed this for a job and didn't want to add a new control page.


Selects the image format for the processed file (and therefore its extension). Appropriate extra controls will appear for different formats.
Warning: The format selection may include output formats that are not installed on your system.
ToDo: fix that.

Common Controls

The Test button processes and displays, but does not save, the first image in the file list. Use this to adjust the settings. Once all the controls have been set as desired, click the Start button. DBP will process each file in the file list. If Show Images is pressed, then the images will be displayed as they are being processed.
Hint: if any process fails, the entire sequence will finish.
Hint: the Cancel button will not respond until the current processing step finishes.
Hint: cancelling any of the processing steps (from the Gimp's popup window for that step) will cancel processing.
Hint: DBP will not overwrite existing images. If you cancel (or decide to repeat) a sequence you will need to delete any output images before starting again.
Hint: the image displays are managed by DBP. Do not draw on, close, or save from them.
Hint: untoggling the Show Images button, or quitting DBP, will remove a leftover display.
ToDo: use separate thread for processing (don't lock up user interface).
ToDo: improve processing feedback.
ToDo: improve error reporting (what error reporting?)


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