i=Import["ExampleData/ocelot.jpg"];
mask=ColorNegate[Image[Graphics[Disk[]],ImageSize->{200,200}]];
finalImage=SetAlphaChannel[i,mask];
Animate[ImageCrop[ImageRotate[finalImage,Pi*n],{200,200}],{n,0,2,1/8}]

With[
{data=Table[ImageCrop[ImageRotate[finalImage,Pi*n],{200,200}],{n,0,2,1/8}]},
Export["~/rotating_picture.gif",data]
]
SystemOpen[%]