The Sidewalk Rescue by Hazel Hutchins, illusrated by Ruth Ohi

From chapters.ca:
When Josie jumps into her sidewalk drawing to pick beautiful flowers, her sister Morgan races to get help. It's a good thing too, because Josie has a great many adventures awaiting her. And when she is chased by a huge and nasty lion, the whole neighbourhood rushes to the rescue. Armed with a box of chalk, they draw all kinds of pictures to help save Josie: a boat at the riverbank to scramble aboard, a giant eagle to pull her from a raging river and an underwater cave to hide her from a shark. Through it all, Josie's spirit is undaunted. When Morgan comes through with the final, ingenious rescue, Josie presents her with the very bouquet she went after in the first place.