Charts out of the GanttProjects projects (.gan) can be exported and saved as separate images in one of the formats that the program supports, which includes PNG images. No 3rd party program capable of working with .gan files is known to us, so this is likely the only choice for gan to png conversion.
Convert GanttProject project plan file to Portable Network Graphic.
We found one software available in the database for this conversion.
Multiplatform software - convert gan to png on any platform
A freeware project scheduling and management program
Convert from gan file format
The table with program actions contains information about what each program is capable of doing with their files. This may be a good pointer for further searches for certain file conversions and help you find the converter you are looking for if our search result is insufficient for you. However, it is far from perfect and may sometimes show results which are not really usable because of the nature of the software handles the files. So a conversion that appears as possible, just because of matched actions, may in fact not be possible.