I draw a picture.

1. A picture is drawn by me.
2. A picture will be drawn by me.
3. A picture was drawn by me.
4. A picture was being drawn by me.

Converting simple present active to passive: object (picture) becomes subject + is/are + past participle (drawn) + agent (by me). Since “picture” is singular, “is” is correct. Simple present passive indicates a habitual or general action—drawing pictures as a regular activity. This transformation is useful when the focus should be on what is created rather than who creates it, common in artistic and production contexts.