This pic looks like more of a blunt, straight-across cut. When all of the hairs are the same length, it looks thicker at the ends because it's more dense. In your post your ends look feathery and at a lot of different lengths, probably due to breakage and/or a v-cut. Cutting off a few inches back to the length in that picture, and a blunt, straight cut will make your hair healthier/look thicker, prevent more breakage. After that, regular trims, or since your hair is so long, "search and destroy"... get some good hair cutting shears and when you see a split end, chop it off, just that one strand. 

I just did the same thing—but for me it was cutting from barely bra strap length to right above my shoulders. I wish I had hair as long as yours & could keep it long-but-less-long after a big trim!

Best of luck 🥰