File with PNG extension contains raster graphics compressed using lossless compression method called ‘deflate’ that supports ‘alfa’ channel and 48-bit color. PNG files can store transparent pixels and 16-bit color per each channel. Each PNG file contains a single image.
After converting the file to the new format, you will be able to use other programs to support it. Keep in mind, however, that the GTX file after converting to PNG may differ slightly from the original. The most important information should be kept, but if you want the file after conversion from GTX to PNG to be the same, you have to do this carefully and choose the proper application from the list below.
There is no guarantee, of course, that the conversion will come up to all your expectations, but it will certainly help you. If, after all, the effect of converting GTX to PNG does not meet your expectations, you can simply try to find on the Internet a different version of your file in GTX format, properly converted to a PNG file by someone else. If this fails, use the information provided in the further part of the website.
Unfortunately, if after performing the two previously described steps (trying to find your GTX file converted by someone else, and the attempt to convert it to PNG on your own) you still have a problem with your file, then there are only a few solutions left. You can once again try to find and install an application that can open the GTX file in its original format (without conversion to PNG file). Such a solution will be difficult to implement, but it certainly will give the best result.