I assume these are self-portraits, based on the images I see on Flickr. The light appears to be primarily blue sky, with you being in the shade. As such, there is a rather bluish colour cast. As a collage, two things stand out for me - the focus is off on the left and right images, compared to the center one (at least the three should have the same degree of sharpness or blurring), and the boundary between images could be blurred to give the illusion they are one image. Alternatively, present them as a tryptich with each image distinct. If you have photo-editing tools, you may want to consider masking off the subject from the background while making adjustments to the colour or brightness - and that may also apply to the rather dark roses.