FMP 12 did have a direct import function for Bento. By chance do you have access to that? I can't recall for certain, but I believe that it too handled images.
Thank you very much for the suggestion. I do have the access to the FMP 12, so I installed and tried it. It does give me an option to covert an existing Bento file, but when I select "Bento data source file" to open, it gives me this error message: "You must have Bento 2 (or a later supported version) installed on this computer," and I cannot move further. My Bento version is 4.1.2, so it is later than 2, but FMP 12 does not seem to recognize it. I have attached the screen short. So I am still stuck ....
Bento import was added in FileMaker Pro 10, and removed in FileMaker Pro 14. Therefore FileMaker Pro 13.0.9 was the last version which supported Bento import. I've run a quick test using FileMaker Pro 13 with Bento 4 and it doesn't do a very good job. First, it doesn't import images. Second, it doesn't work properly in OS X 10.10 (Yosemite) or later, so you need a Mac running OS X 10.9.5 (Mavericks).
The Bento 4 to FileMaker Pro Migration Tool (linked from the article referenced in the original post) does a much better job. It requires Bento 4.1.2 to be installed (along with the Bento database in its usual location) but does not require a copy of FileMaker Pro. I tested it on a Mac running OS X 10.9.5 (Mavericks) and it converted a Bento library to a .fmp12 file which opened fine in FileMaker Pro 15. The converted database had images in the records, and the resulting layouts looked much closer to the Bento forms.
The Bento to FileMaker migration tool did not work for me in macOS 10.12.2 (Sierra) - it crashed. According to a support document linked from the migration tool page, it will work in OS X 10.10 (Yosemite) as long as the address book integration in Bento is turned off, but that didn't help for me in Sierra.
I ran into the same problem with FileMaker Pro 13 complaining that it needed Bento 2 or later. It turned out that was caused by having Address Book integration enabled in Bento, but turning it off didn't actually help much: FileMaker Pro got as far as recognising the Bento libraries and importing the record structure, but didn't import any data. According to the support articles, you basically can't import from Bento unless you are running an older version of OS X (see my other post for details).
If you don't have access to a Mac running Mavericks, running it in a virtual machine might be an option. If that is not convenient, I already have one set up and would be happy to help convert your data.
Thank you very much for your kind offer. I would like to ask you the conversion if that is ok for you. Could you tell me how we can exchange the files?
I happen to have a Mac that still runs OS X 10.11.4 (El Capitan), so I tried The Bento 4 to FileMaker Pro Migration Tool anyway. But the migration tool did not work. It just crashes. This is perhaps expected as you and the link mentioned it is supported to work OS X 10.10 (Yosemite) but it does not mention El Capitan. So after all I am stuck and I need the help.
(I am off line for a while so my next response will be a bit delayed. 5:42pm)
All done (via private messages and Dropbox). Please let me know how it turned out.
Thank you very much, Dave! All of my Bento data, including the images, is converted nicely to FileMaker file This saved lots of time for me. Thank you very much for your quick and accurate support!
One lesson learned was: Do not wait till end to migrate new SW
Since I am rather new to the recent FileMaker (I used to use it 25 years ago on my SE30) so I have to get myself familiar to it. The concept and the structure seems a bit different from the simple plane database, so I will learn it.
Again, thank you very much!