* image.c (Vmax_image_size): New variable.

* image.c (Vmax_image_size): New variable.
	(check_image_size): New function.
	(xbm_read_bitmap_data, pbm_load, png_load, jpeg_load, tiff_load)
	(gif_load, gs_load): Use it.
	(lookup_image): Try loading again if previous load failed.
	(xbm_read_bitmap_data): Add a new argument, a pointer to the frame
	to display in, NULL if none.
	(xbm_load_image, xbm_file_p): Pass xbm_read_bitmap_data the new
	argument.