By default, the Opaque property is False. The Opaque property indicates if the picture is shown as opaque or transparent.

If using the PNG format, the control handles automatically its transparency / alpha blending, unless the Opaque property is True, so in this case, any TransparentColorFrom or TransparentColorTo property has no effect. 

For any other picture type, you can use any of the following to define the transparent region of the picture:

• TransparentColorFrom, specifies the transparent color to define transparency part of the current picture (to). 
• TransparentColorTo, specifies the transparent color to define transparency part of the current picture (to).

The control supports almost all type of pictures like

• PNG (Portable Network Graphics) is a raster graphics file format that supports lossless data compression. PNG was created as an improved, non-patented replacement for Graphics Interchange Format (GIF), and is the most used lossless image compression format on the Internet
• BMP file format, also known as bitmap image file or device independent bitmap (DIB) file format or simply a bitmap, is a raster graphics image file format used to store bitmap digital images, independently of the display device (such as a graphics adapter)
• JPEG file format (seen most often with the .jpg extension) is a commonly used method of lossy compression for digital images, particularly for those images produced by digital photography.
• GIF ( Graphics Interchange Format ) is a bitmap image format that was introduced by CompuServe in 1987 and has since come into widespread usage on the World Wide Web due to its wide support and portability.
• TIFF (Tagged Image File Format) is a computer file format for storing raster graphics images, popular among graphic artists, the publishing industry, and both amateur and professional photographers in general.