raw images in photoshop CS6

Hello, I just used my new Canon EOS 7D Mark II last night for the first time, using the settings where the camera saves the images as raw and jpeg.  I have never shot raw images before and wanted to try it out.  I put the images on my MacBook Pro, like I always do, both jpeg and raws. I selected the images I wanted to edit and tried dragging and dropping them into photoshop like I always do.  When I did this, a different screen popped up, asking me to open, edit, close.... with editing functions on it.  I clicked open and put them into my normal editing area, edited them, and saved them.  They all went from ~15MB down to ~5MB and turned into JPEG.  I dont know why, but they also shrunk in file size when I put them into photoshop.  Can you help me figure out what I am doing wrong?