The batch features of IrfanView are very powerful, but easy to use. Be very careful if opting to overwrite files though, as you can very quickly destroy your original images (>_<). You can also use the batch feature to rename images (and other file types).
1. Select Batch Conversion/Rename from the file menu (or press B) to open a dialogue box like that below. Browse to find the files you wish to convert, and select them in the file list window.
2. Click on Add to add them to the Input file list.
3. Browse to choose the Output directory, or click on the "Use this directory as output" to use the input directory as the output directory too.
4. Choose the output format from the dropdown list and click the Options button to view the available options for that file format.
For JPG image output you can choose the quality. A value of 50 gives decent results for most photos. Use a value of 75 or more for images having sharply contrasting areas of colour.
Check “Try to save with original JPG quality (estimation).” IrfanView will then bypass the quality slider and try to save the converted image with the same JPG quality/compression value as the source image. There is nothing much to be gained by saving a low quality image at a high quality. Existing artefacts will not be removed, but the file size will increase substantially.
"Save as progressive" makes the image draw more quickly on the web.
5. Click the Set advanced Options button to display this dialogue.
Here you can change many aspects of the image. I have opted to crop some 1280 x 1024 images to 1024 x 768 pixels and then resize them by 50%. Check "Use Resample function" for best quality.
As you can see, there are lots of other options for rotating, flipping, adjusting, and recolouring images.
In the miscellaneous section check "Overwrite existing files" if you are converting to JPG. The Tiff files won't be overwritten, only JPG files of the same name if they exist.
Open the Change Order dialogue to choose which batch operation to perform first. This is new to IrfanView version 4.33 so check for updates if you’re still using an older version.
6. Click on OK to accept the advanced options, then click on Start in the first dialogue box to start the conversion process. You will see a progress report dialogue.
It will generate errors if the requested operation could not be completed, and give warnings if files have been overwritten as requested.
While the batch process is running, you can click on Stop, and return to the batch dialogue to correct any settings that are causing too many errors, or to add some files that you missed.
Sorting Files for Batch Operations
There are two ways to sort files before running batch operations:
From the Thumbnails Dialogue
Open the thumbnails dialogue from IrfanView, and select the sort order from the Thumbnail Options menu, Sort Thumbnails submenu.
You can sort by any of the options shown on the menu, either by ascending or descending order.
After selecting the images you want to process with the batch operation by using Ctrl + Click and/or Ctrl + Shift + Click, from the Thumbnails File menu, select: "Start batch dialogue with selected files (Shortcut B)"
The batch dialogue will open and the filenames will be loaded in the chosen order. Set the output format, output directory, and the advanced batch options before running the batch operation.
The advantage of this method is that you can see the thumbnails of the images while sorting the files.
From the Batch Dialogue
With or without using the Thumbnails view, open the batch dialogue. Click on the View menu to the right of the Look In directory field, and select "Details" from the View menu. This will list the filenames only without thumbnails, with the default column headings of Filename, Size, etc.
Right-click on the column headings to open the column headings menu, and choose any of the available column headings, or select the More... option to get a dialogue with more options, including the Date Picture was Taken.
After selecting the headings you need, and deselecting the headings you don't you can drag the column headings to left or right, and sort the files by any column heading.
This method offers more sorting options, but doesn't allow you to view the thumbnails while sorting. However, after sorting, you can switch back to thumbnail view from the View menu, and the files will remain in their sorted order while showing the thumbs.
Important Note: When adding the files to be processed, don't use the Add All button as this will just add them in filename order. Select the files using Ctrl + Click and/or Ctrl + Shift + Click, and add them to the list of files to be processed using the Add button.
Batch Renaming of Images
1. The same batch process dialogue box (B) is used to rename images too. Not only images, in fact, but any file types can be renamed. 2. Browse to the directory containing the files you want to rename, select them in the file list window, and add them to the Input files list.
Select "Batch Rename" and enter a file name pattern, or click "Set rename options" for more options. Click the Start button to rename the selected files. You will get a similar progress report to that illustrated above, telling you whether or not the operation has been successful.
The Set rename options dialogue box allows you to set a starting number other than 1 for the file name suffix (or prefix).
Click on Help for more advice and options, e.g.
"Please be very carefully when you use rename and first test your options with dummy files; batch rename can be very powerful = dangerous! Using bad name pattern, combined with options like Rename-Move original/input files and/or Overwrite existing files, you can, under special circumstances, remove all input/original files! Please do not use these options, until you REALLY know what you are doing. "
A Word of Warning
Renaming and Conversion of images can be combined in a single operation. In the Batch Process dialogue box, select "Batch conversion - Rename result files." Both operations will be performed in one operation.
While you're learning to use this powerful feature, don't be tempted to overwrite files unless they are unimportant or backed up on CD. Advanced options that you used previously may still be in force, and you may not get the intended result unless you check all the options carefully.