[Free] ImgToBBHost Extension

I meant the SimpleBase641 extension used in the google sheets upload example.

Yes, but that only works for images, which should be OK for this application

Sorry, didn't know that was a unacceptable question.

Is there a difference between KYO4_Simplebase641 and simplebase641. there is no Decode block in KYO4_simplebase641.

As advised above:
You do not need to decode the image when you get the file back from imgbb.

Juan's base64 extension allows for conversion to and from base64

http://kio4.com/appinventor/277_extension_imagen_string.htm

the simplebase641 extension also provides a decode method: