Whilst technically probably possible, PNG to EPUB conversion is not something that would be usually done. Because what the conversion would do, is to put images on individual pages of the book - without text. The resulting file would most likely be very large.
Convert Portable Network Graphic to Open Publication structure eBook.
We have found one software suitable in our database for this conversion.
Microsoft Windows software - convert png to epub on Windows
Kindle Comic Converter is a Python app to convert comic/manga files or folders to EPUB, Panel View MOBI or E-Ink optimized CBZ.
Convert from png file
to epub file
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.