Slideshows are made for the device itself (if you are talking the standard ones) and can't really be sent. They are not actual true slideshows, it is just a way of organizing the images you have on the device, well the ones you chose to include.
You can, however, try getting a slideshow making app from google play. Make sure you get one that allows you to create real sharable slideshows rather than just letting you organize your images into one. A real slideshow will also be a larger size file when done. As it has to include all the images you have added to it. So keep that in mind. Most places have limitations on file sizes. Also, make sure the app you are creating it with doesn't require the other person have that app as well. Otherwise the other person may not be able to view it.
There are other ways to do this, like creating an animated image (not moving or dancing, just changes photos) file. I have not tried the apps for Android devices to make something like that, however there are some good (and free) ones you can use on a computer and then share the file on any device.