Love love love this app!
It has everything you need to create designs from scratch or convert from images.
It has loads of import options that allow you to refine the photo conversion, even more than many paid apps. Then you can edit the designs with various stitches including back stitches (those long line ones) so you could do blackwork or outline things in addition to cross stitch.
The export function is extremely robust with options to export as pixel art, as an image, or as a fully featured pdf with controls for everything like symbols, colors, black and white, how to split the design between pages, a logo for your brand etc.
Plus! I suggested a few features to the developers and they were in the VERY NEXT UPDATE. Amazing!
Love the app.