SetDirectory@"C:\\drorbn\\AcademicPensieve\\Classes\\23-FastComputations"

col=ImageCollage[
Scaled[1]-> ImagePad[#,8,White]& /@ ImageCrop /@ Import /@ FileNames[{"*.png","*.jpg"}, {"Day1Gallery"}],
"Fit", 300{8,11.4},
Method -> "ClosestPacking",Background -> White, Padding -> Red, ImagePadding -> 4
]

Export["Day1Gallery.png", col]