The ability to see specific items in an aerial image is mostly a function of scale and resolution. The following aerial photography products all have a resolution of 1 meter or better, so you should be able to see an object the size of a house:
- High Resolution Orthoimagery (HRO)
- National Agriculture Imagery Program (NAIP) imagery
- Digital Orthophoto Quadrangle (DOQ)
Use EarthExplorer to search for the aerial photography resolution that fits your needs. In the "Additional Criteria" tab, indicate the desired scale range using the "Scale" option. Scales of 1:500 to 1:24,000 are best for identifying buildings. Scales of 1:20,000 to 1:80,000 work well for agriculture and geologic interpretation. Scales in excess of 1:100,000 provide regional assessment information.
Enlarging an aerial photograph will only make the object bigger; it will not add more detail in the object. Photographic resolution (image resolution) deteriorates with each enlargement.