Invitations are often the first thing that get decided for a party. They generally set the tone for the celebration...whether to convey a mood (think dressy casual supper), define a theme (like the dog days of summer) or establish a color palette. That's why they can be one of the most exciting (and stressful) parts of party-planning!
Some people set out to buy an invitation with an idea of what they are looking for. Others decide the direction of the party based on the chosen invitation. And for those crafty few with a very definite opinion(who don't mind spending some extra hours), they make their invitation!
Amy's party already has a couple of key things established, including: 1) the 'where' (their house) and 2) the 'what' (dog days of summer 1 year old birthday party). Her son, Jack, is in love with their family dog, Otto, who is a dalmation-mix. My guess is that Amy will want to incorporate Otto into the celebration, and may even have him serve as the mascot! Since dalmations already come with a preset color palette (black and white...and often fire-engine red), it gives Amy an opportunity for an 'easy button' color scheme.
Above are some favorite choices for dog-themed celebrations. From top: bone-shaped paper clip (great for attaching a picture or directions), fire engine & dalmation invitation from meri-meri, tartan plaid invitation from stacy claire boyd, brown puppy-dog invitation from checkerboard, and a dalmation invitation from drenculture.