There are 3 settings for photos inserted into RainbowNote.
① use photo trimming or not.
② max width and height/
③ file format.
Touch "Photo Settings" button in Settings page (you can open it from touching gear icon of List page).
If the export format is "Png / Jpeg" and the file size of the photo in Png format is bigger than 500k bytes, Jpeg format is used for uploading to Google Docs.