I do not wholeheartedly disagree with Kevin and if you are not sure, using a single neutral color on walls and ceilings throughout a home will certainly not get you in trouble. And as suggested, use color accents in pillows, art and things to make changes. Then take a nap because it does get BORING.
I could make your rooms seem much larger just by playing with color flow and much bolder values of color. I might have to change at least some of your ceilings from white to something else. Depending on how tricky I wanted to be and how much I also played with lighting? That ceiling fan, for example is really reinforcing your low ceilings to an uncomfortable point and those lights on it in the center of the room are doing no real good. You could distribute the light where you could really use it with some floor or table lamps or even a clever sconce or something.
White ceilings and an elaborate multi-bulb ceiling fixture right in the middle of the room really date back to the days of gaslight fixtures when they had to be there less you burn the house down. And you needed as much light reflected from them on a white background as possible. Nothing in a home makes less sense with the exception of perhaps the evolution of the old icebox. You open a humungous 9,000 cubic foot thing to grab a can of soda. Why not have smaller distributed refrigerators? How often, for example do you open yours for meat compared to milk or something to drink? Let's move on please.
I could make your living room look 400x400 with a glimmering hopeful bedroom off of it. Just playing with paint. And if you were a client we would talk about when and how you use the different rooms so I knew about color of light and your color rendering index for the times you are in the room.
The idea to take some sharper pictures and color correct them is great. Then do put them into one of the simulators. I use Benjamin Moore's the most but they all work the same. Color Impact from Tiger Color in Oslo is my fave go to exploration tool. And of course www.easyrgb.com
is free and great if you take Blondsense's advice and scour magazines. Pick a color pixel from a photo you like, run the rgb code through easyrgb and it will kick out the four closest paint names, swatches and numbers from the company whose virtual painter you are using.
And if you are not sure? Try one of those paint samplers or a quart of something. People like me and interior designers can get you large 8x8 swatches of things for free. A real paint store will sometimes order them for you too. I have a masters in fine arts with a concentration in theoretical and applied color theory and have been working with it for decades at times to make a living. I cannot make a decision based on those tiny strips and chip things. And those who think they can pick colors in the store are absolutely psychotic and delusional. You have to take some home. And you know, a better idea if you shop at a real paint store is to borrow the whole wall full of color in the form of a fan deck or two. They will gladly lend you one.
Think about working with an interior designer. They are not just for the rich and I have enjoyed all that I have worked with and especially those who helped make my interiors special. Most work mainly off commissions of wholesale things they buy for you and I have always ended up cheaper than if I tried to buy retail myself. Of course in color consulting they and architects are my clients so it works out.
Have fun. Sometimes small little houses like yours are the most enjoyable. I always loved working on them.