Dear Jilly -
Intriguingly the only reason I used that chocolate covered strawberry is a certain someone here in this forum asked for chocolate on the cover
I was going for healthy items so that was my compromise. I do think it's nice that it has a sense of "motion" to it where the rest are static.
It's an intriguing thought about the series having all the same color fonts. My thought on that goes along these lines. Each cover has to be absolutely perfect on its own because this could be the first cover a person sees and their sole decision could be whether to click on that cover or not. So the cover has to be ideally optimized for the color match between the item and title. If I used a non-matching color for the tomato they wouldn't realize it was because of a series, they would just see that the color wasn't a match and the effect would be less powerful.
The cover I like a lot that is on this same theme has grey letters -Good Calories Bad Calories
But I didn't want to go that route. Still, as I was playing with color choices for the title (for *far* too long!!) I found that bright colors seemed to look non-professional to me. The very muted ones gave the more professional feel, to my eyes. So that's how I ended up with that one. When I made it a stronger color it no longer felt like a professional cover to me. Maybe I should make it a greyer color of tomato-orange ...