Hi Rabina, the footprints you mapped here all represent buildings and are appropriately squared, however many of them could be more accurate for one reason or another. 

It looks like you do not understand how to account for off-nadir imagery i.e. imagery taken at an angle, when mapping. Consider the Tower of Pisa, when mapping footprints from imagery like this the roof can be used to obtain the building's shape, then it should be moved to the base of the building so that they are accurately positioned. In this case the Southern and Western walls of buildings can be seen and the shadows are cast North so you can sometimes see where the shadow originates at the base of the Western corners of buildings. Sometimes you included the wall in the size of the footprints leading to them being oversized. This [video about mapping dense urban areas](https://youtu.be/JAPiGntG6fs) has more information and a guide.

I think you generally map building footpritns oversized. 

When mapping buildings, please trace the shape accurately. Accurate building footpritns aid population estimates and prevent issues like data overlaps. Zoom in so that you can see the outline of the building and mark the corners carefully. Exclude shadows and yards when tracing the footprint.  Keep in mind that you are looking at the roofs of buildings, but mapping their footprints. Depending on how the scene is lit, pitched roofs may have light and dark sections that belong to one building. Generally pitched roofs overhang the walls of a building, so a footprint slightly smaller than the roof is accurate. You can scale selected features in ID with shift+(-/+), or JOSM with ctrl.+alt+Lclick & drag.  Take care to make contributions that others can build upon.

You mapped some more complex buildings as simple rectangles. Do you know how to use the extrude tool or draw complex buildings in JOSM?

Please keep this feedback in mind when contributing in future. Thank you for your contribution. If you want to experience the OSM community or to get timely feedback from other mappers; I recommend that you attend a mapathon. You can find events here https://osmcal.org/