ImageAssemble
ImageAssemble[{{im11, ..., im1n}, ..., {imm1, ..., immn}}] assembles a single image from an array of images.
ImageAssemble[{{im11, ..., im1n}, ..., {imm1, ..., immn}}, fitting]assembles images using the fitting method.
Examples
Assemble images into a grid:
ImageAssemble[{{img1, img2}, {img3, img4}}]Create a 2x2 mosaic:
imgs = Table[ExampleData[{"TestImage", "Mandrill"}], 2, 2];
ImageAssemble[imgs]Please visit the official Wolfram Language Reference for more details.