Read the case description. Picture is useless. Picture can have rainbow or solid color as chosen by the photographer, not a representation of exactly what fan is included unless it's #1. There's 3 kinds of lighted fan...
1. LED. Basic, single color, sometimes come with available on/off. Can be rainbow colored, but not changable rotation nor colors.
2. RGB. Analog switching, uses motherboard supplied amperage control. All leds in the chain come from a single source, so all leds are the same chosen color.
3. ARGB/DRGB. Digital switching, uses software supplied pwm control. All leds in the chain are controlled seperately, so each led responds to software control via addressing. The Only way to achieve jrainbow affects that are changeable.
So an RGB fan, all the leds can only be whatever actual color you chose, no patterns, no rotation, no rainbow. ARGB/DRGB each individual led on the fan is seperate, so can do patterns, rotation, rainbow. Just because the picture doesn't show rainbow, doesn't mean it cannot do it. Have to check the case description and the included fans. Many fans have no included lighting.
And yes, you can change out fans. A fan is a fan. Any lighting is just leds glued onto the fan and is controlled seperately, except #1.