Compression

BMP 87K

GIF 49K
BMP usually uses no compression, though seems to have something or it would be larger. GIF uses classical (lossless) compression.

JPEG 13K

JPEG 9.5K
The larger JPEG looks fine, but takes just over a fourth the space and transmission time of the GIF. On the smaller JPEG, look for artifacts around the top of the house that look like ripples in the background. You can also see some graininess on the side of the house and elsewhere.

JPEG 2.8K

JPEG 1.7K
These are nice and small, but the data loss is pretty blatent.