TransparentPNG

TransparentPNG is a compact and portable application that you can use to create PNG files from BMP in batch mode.

It comes packed with several useful settings that can be adjusted by all types of users, regardless of their level of experience.

Since installation is not required, you can drop the executable file anywhere on the hard disk and click it to run.

It is also possible to save TransparentPNG to a USB flash disk or similar storage unit, to be able to run it on any workstation easily, as long as it has .NET Framework installed.

An important aspect to take into account is that the Windows registry does not get updated with new entries, and files are not created on the disk without the user's consent.

The interface is based on a regular window with a plain and simple layout, where the conversion process is broken down into three steps. You can get started by selecting the BMP-containing folders and letting TransparentPNG automatically detect all supported files. Their file paths will be displayed in a queue, and you can adjust the white tolerance level.

In the following steps you can proceed with the PNG conversion, after which you can open the saved files' location in Explorer. A "before and after" preview panel is available as well.

TransparentPNG does not take a long time to complete a conversion job, and it uses low CPU and RAM. Unfortunately, the tool popped up an error and crashed in our evaluation (on Windows 7 64-bit), as soon as we started conversion. While ignoring this aspect, TransparentPNG comes packed with some helpful options for turning BMP files into PNGs.