Have you read the 1971 Caldecott Honor Book, Frog and Toad Are Friends by Arnold Lobel? Keep an eye out for many well-written books by this author at local sales or visit your library for these. I love books about friendships, especially with animals.
For sure, with the above pictures you can see the difference between a frog and toad.
About The Book:
"One summer day Toad was unhappy. He had lost the white, four-holed, big, round, thick button from his jacket. Who helped him look for it? His best friend, Frog. Another day, frog was unhappy. He was sick in bed and looking green. Who gave him some tea and told him a story? his best friend, Toad.
From the first enchanting story to the last, these five adventures of two best friends are packed with excitement, gaiety, and tender affection. Children will find this book delightful to read and beautiful to look at, either story to story, or from cover to cover."
-- Lady D