Opening Files
The Image Browser
The Batch Browser
Batch Processor
Drag and Drop
Saving files

Opening Files

To open a new image in PD Pro, select Open from the file menu.

You are presented with a standard dialog box that you can use to select your file.


Use the “Files of type” drop-down control to select the type of file you want to load.  Howler saves the Truevision Targa format by default.  Targa format is a flexible and widely supported format for graphics exchange, used commonly in the computer graphics industry.  There are lots of other formats supported too, in fact around 60 of them.  If you want to open a Jpeg, Tiff, or any other supported file, just select 'Automatic' from the list.

Layered format is a special format used for loading and saving files that contain separate layers.  If you are using layers and want to keep them separate, without merging them, then use the layered format to save a copy of your file.

Dropping down the control on the top right of the dialog box lets you select several ways of displaying the contents of the folder you are browsing.

 For example, you can display certain types of files (bmp, jpegs, gifs, png's) as thumbnails.  This is a feature of the operating system.  A dedicated image browser is also included and will be explained below.

Selecting Details gives you a lot more information about your files.  Included is the file type (determined by the file extension) and the file size.  The date of the files creation, or the last time it was modified is listed, and the dimensions of the image (of supported files) are listed to the right.


Right clicking on a file will give you a context menu of various options.  This will often vary from system to system, but a number of features remain the same.

You can select the 'Preview' item to open an external application to view the file.  Whatever program that is associated with the file type by the operating system will be used to show it.

The little doodad at the bottom corner of the window, under the open and cancel buttons, lets you change the size of your window, so you can show more files if you want to.

Pattern Matching

If you wish to list files of only a certain type, say Jpeg, then you can use Pattern Matching.  In it's basic form, it can be used like this...


Adding "*.jpg" to the filename control causes the dialog box to list only files with the extension ".jpg"

There are many other possibilities with pattern matching.  Suppose you want to list only files that begin with the letter B, use "B*".

Browsing with the Image Browser

A dedicated image browser is available from the file menu.  Select 'Browse' to open it.

The image browser lets you see thumbnail images of every supported file type, and it can be kept open while you work, so you can select files at any time.


Use this list to select the folder where your images can be found.

The drop-down control at the top lets you select the device, such as hard disc or removable drive.

If you prefer the standard folder browser, or if you need to browse a network for your files, you can access it with the button.

You can select the types of files you want to see as thumbnails.  The default is Targa, but you can select a number of file types.  You can also type in a file type that is not shown, and if it is supported by the converter, it will be displayed.  For example, a number of Unix formats are supported that were left out of the list for simplicity.  You could type '*.SGI' to load a Silicon Graphics file.

It can take a long time to generate all the thumbnails when there are a lot of files in your folder.  You can stop the process at any time by selecting the Stop menu item.

You can also restart at a later time.

The 'explore' option opens a standard browser to view your files with the operating system.

'Path to clipboard' copies the name and file path of the currently selected thumbnail to the systems clipboard.  You can then use it if you want to load the file with another application.

You can display smaller version of the thumbnails by selecting the 'Small icons' menu item.

Drag and Drop

Drag and Drop lets you select a file in the OS's "Explorer", and drag it onto the program to be opened. Drag a file from Windows Explorer onto the Howler program, and it will be opened automatically.

Saving Files

The save dialog box differs only slightly from the open dialog box.  Select Save from the file menu to save a file.

The difference, is now you want to manually select what file format you want to save.

The default format is Targa.  It is a widely used, lossless 32 bit format.  The image is saved as 3, 8 bit channels, red, green, and blue.  The fourth channel is an 8 bit alpha channel.  The alpha channel is used as a 'selection' in the program.  Alpha channels are often also used for transparency.

The Layered format is a proprietary format used when you want to save an image that contains multiple layers.

The default Targa saver offers a number of options for saving your files.

With Targa files, you have a lot of control as to how the image is stored in the file.  You can save all 32 bits of you image (8 bits of red, green, blue, and alpha) or you can save the image only, or just a single channel of grayscale.


8 bit (color) converts (quantize) your image into a single 8 bit channel that uses a look-up table (LUT) to decode color information.  This is commonly referred to as a color table.  The advantage of doing this, is the file size is cut by 1/3 or 1/4.  The disadvantage, is that color information is lost in going from 24 million colors down to 255.  on the other hand, the results can still be quite good, because not many images actually take advantage of all those colors.

8 bit (grayscale) drops the color information by averaging each channel into a grayscale image.  The file is then saved in 8 bites per pixel.  This can represent a nice savings in size if you do not need color.

24 bit color images are saved with the red, green, and blue channels, but not the alpha channel.

32 bit color images look exactly the same as 24 bit, but the alpha channel is saved along with them.

Bmp (or Bitmap) is a format made popular by Microsoft Windows.  The saver will save BMPs in 32 bit format.  The alpha channel is supported if you have one active when you save.  BMP is a lossless format, although it may or may not be compressed with RLE (run length encoding) compression.

Jpeg (or jpg) is the format of the Joint Photographic Experts group.  It is a lossy format (meaning image data will be lost every time a file is saved or re-saved.)  Compression ratios of 10 to 1 are not uncommon.  It is the preferred format for working with images for the web, because of the smaller file sizes.  The alpha channel is not supported in this format.  The jpeg baseline standard is supported, and you can set the quality using the panel that is opened.  Moving the slider to the right gives you a higher quality, at the expense of a larger file.  Values in the range of 60-90 are common.

Selecting “Settings” under the window menu will give you an option to set the default Jpeg quality.

PNG is a newer format, designed to be more flexible than older formats used on the web.  It supports various bit depths, and even the alpha channel, while offering good compression ratios.  Your files will be saved in 32 bit format.

PSD (Photoshop Document) format is supported in a baseline single layer.

Targa is also supported externally, as well as internally.  Use of the default targa saver is recommended.

Tiff, the Tagged Image File Format is a very flexible, form and chunk based format.  Just about any information can be stored in a tiff file, however it is presented here largely for loading and saving 32 bit images.

If you try to save a file with an extension different than the one specified, the correct one will be enforced.  For example, if you type “MyFile.jpg” when you have Tif selected as your file type, the filename will be changed to “MyFile.tif.”

Using the Batch Browser

Sometimes, you not only want to select files, but you also want to manage them, copy them, or convert them to another file format, or rename them. This is not easily done when you have to do it one file at a time.

The Batch Browser lets you perform batch operations on a number of selected files.

In addition to copying and deleting files, like you may do between instances of other browsers, the Batch Browser also lets you...

  • Batch rename

  • Batch convert

Start the Batch Browser from the file menu. You are presented with a typical “explorer” like interface. Across the top you may find different folders you can open. Under them are the files you will be working with. They will usually be organized into groups of different file types, such as “Bmp”, “Jpg” etc.

On the left side are several important areas you can search for files, such as the desktop or the whole computer. There is also information about the file that is selected.

On the top/left is the list of jobs you can perform on selected files. If you have more than one file selected, the job will be preceded with the word “Batch”, as in “Batch Rename”

The Batch Renamer

If you need to rename a series of image files, you can use Batch Rename. First, select the files you want to rename in the Batch Browser, and click Batch Rename under “Jobs” on the left.

The Batch Renamer shows you the list of files you selected on the left. On the right is how the filenames will appear when renamed. The files are not renamed until you click the “Rename” button to dismiss the panel.

In the “New name” area below, you can tell the renamer how to rename your files.

The “New base name” text string is where you enter the base part of a filename. When you rename the files, this base name will have numeric digits applied to it, such as “001, 002, 003...”

The “Digits” button tells the renamer how many digits to use in the number. 2 means the number will look like this: “01.” 3 means it will look like this: “001.”

The “Start on” button tells the renamer what digit to start on. This is usually zero, but you can start on any number.

What if you do not want to create a new filename, but want to modify an existing filename? No problem, just check the “Change an existing name” check-box. This tells the renamer not to create a new name. Instead, it will use the existing filename for each file you are renaming, and modify part of it using a specified pattern.

For example, you can replace part of a word by specifying the part you want to replace in the “Replace” text box, and placing the word you want to replace it with in the “With” text box.

Batch Convert

To convert images to a different format, simply select them, and select “Batch convert.”

You are presented with a panel that lets you see a list of the files you have selected. Simply click on the option button for the format you want to convert to, and click the Convert button.

If you want to copy the new files to a new folder, click the “Convert to new folder” check box, and provide a path to the new folder by clicking on the folder icon.

The Batch Processor

The Batch Processor supports wildcard pattern matching, to help refine your list of files to select from. In addition to the given wildcards, you can type in a new one.

Internally, the Batch Processor is a command line front end. The command line it produces can be viewed through Howler's Error Console. Look under the Window menu/Other/Error Console.

Sometimes you want to do more complex operations on a series of files, or sometimes you need more advance file format support. The batch processor exists for just such an occasion.

Bare in mind, if you want to perform image processing on a series of images, you can often load them as an image sequence, and process them with Howlers native tools and filters, provided the images are all the same size. Then you could simply save them out again as a new image sequence.

However, if you need to work on files that are all of different sizes, again, there is the Batch Processor. With it, you can perform many image processing operations, or you can simply convert to a different file format.

Sometimes, when working with a large number of files, it may be too complex to work in a visual environment like the Batch Browser. The Batch Processor simply works with file names instead of icons, so this can save some complication.

On the left is a representation of your filesystem, where you can select your source folder and files. Next to it is the area where you individually select the files you want to process. You can shift or CTRL click to make multiple selections, or you can click and drag up or down also to select files. On the top right is the list of image processing operations to perform. You can perform more than one at a time.

Below that is the save format you want to use. You will need to select a save format to proceed.

If you want to save the files to a new folder, be sure to check “Use dest folder,” or the files will be saved in the original folder.

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