Photo Quality guidance/advice

You have some fierce competition from other Frog inventory. Examine what they're doing differently, and work on it.

https://stock.adobe.com/searchk=frog+photograph

While convenient to use, phone cameras are very limited in what they can do. To get good results, the conditions & light source must be ideal. If you're serious about pursuing Stock Photography, start saving for a good entry level camera and lenses (new or used). Consider enrolling in some online photography courses to learn the fundamentals of composition, lighting and photo technique.

Hope that helps. 

I think you might have used the Portrait mode on the iPhone which results in too many areas being out of focuse as noted here.

A few appear to be a bit soft or have exposure issues. Cell phone images are sometimes accepted but they always need some post-processing.

All photos need to be reviewed at > 100% to check for noise and sharpness. You also need to check exposure to ensure that highlights and shadows are correctly exposed. Try to follow some basic composition rules. Do som type of post processing to correct the photos. That are all the tips I can give you.