Although it's free and performs well, TGMDev's PhotoRenamer isn't for casual snapshooters, but its sophisticated batch renaming capabilities will suit professional photographers and advanced amateurs with a large image archive to manage. PhotoRenamer's Renaming Masks automatically rename batches of images with date and time, either from image data or EXIF metadata, based on strings of characters separated by the % symbol, such as %Y for Year with century or %y for Year without century. Three Masks are provided at startup, but you can add and edit up to 40 custom Masks.
PhotoRenamer's user interface is a bit busy at first glance, but an Office-style Ribbon toolbar and a bit of practice make things easy enough to pick up, and an extensive Web-based manual and support options are available when needed. You can quickly change the background image from the View menu as well as toggle through several display options. Closing the Application Log pane at the bottom of the program's window and making some other changes cleaned up PhotoRenamer's layout a bit. The Options menu let us configure how PhotoRenamer handles duplicates, including color-coding stacks of very similar images (such as rough sorts or burst-mode series) as well as adding suffixes and more. Some of these steps seem complicated, but balloon messages appear with extensive explanations when you hesitate over a feature.
But even with such great touches, PhotoRenamer still emphasizes flexibility and performance over convenience. For instance, the File Selection Filter lets you specify certain image types, such as JPG. But you must type in *.jpg (PhotoRenamer 3.3 supports multiple filters separated by semicolons) and so on, and edit masks with similar methods. Easy enough; but if that's just not your thing, free tools with fewer options are plentiful. If you require something extra, PhotoRenamer has it.