Hi @reajulbracupg,
As far as you don’t use the image/photo data the data itself would not consume large space. Besides, if you download and delete all the data once they have been backed up to your device the storage would reset to 0. So you could also use your KoBoToolbox user account by collecting data>backing up data in your device>emptying data from the KoBoToolbox server>collecting data.
Have a great day!
