Hi
You could write a node that publishes your images one after the other and then launch that node from a launch file.
To do that you can probably follow this tutorial and modify it to loop through your images.
I haven't tested any of this but I guess you would have to change cv::Mat image = cv::imread(argv[1], CV_LOAD_IMAGE_COLOR);
to something like :
cv::Mat image1 = cv::imread(path/to/image1, CV_LOAD_IMAGE_COLOR);
cv::Mat image2 = cv::imread(path/to/image2, CV_LOAD_IMAGE_COLOR);
cv::Mat image3 = cv::imread(path/to/image3, CV_LOAD_IMAGE_COLOR);
and then change msg
at a regular time interval in the loop