I am planning to buy a Stellina telescope, but recently I find the EvScope, the photos are less quality in EvScope, is for the processing?

For photography, the Stellina has a better sensor and will give higher resolution images. If you do not care about the "eyepiece experience" (although it still isn't the same as a real eyepiece) and really prefer images, then I would go with Stellina. See some examples of images here.