Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate FujiFilm S2500HD and Pentax Q side-by-side from the front, back and top in their relative dimensions. FujiFilm S2500HD has external dimensions of 110 x 73 x 81 mm (4.33 x 2.89 x 3.19″) and weighs 337 g (0.74 lb / 11.89 oz) (including batteries). Pentax Q has external dimensions of 98 x 57 x 31 mm (3.86 x 2.24 x 1.22″) and weighs 180 g (0.40 lb / 6.35 oz) (including batteries).
Below you can see the front view size comparison of FujiFilm S2500HD and Pentax Q. Pentax Q is clearly the smaller of the two cameras. Its body is 12mm narrower, 16mm shorter and 50mm thinner than FujiFilm S2500HD. As you can tell, actually this is not a fair size comparison since FujiFilm S2500HD has a built-in lens but Pentax Q doesn't. Once you put a lens on Q, its thickness will increase significantly.
Here is the back view size comparison of FujiFilm S2500HD and Pentax Q.
Now lets look at the top view comparison of FujiFilm S2500HD and Pentax Q.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Pentax Q is significantly lighter (157g ) than the FujiFilm S2500HD which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on Q, the total kit will weigh much higher.
Unfortunately neither FujiFilm FinePix S2500HD (FinePix S2600HD) nor Pentax Q provides any type of weather sealing in their body, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Bridge Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
FujiFilm S2500HD and Pentax Q's LCD screens has the same diagonal size of 3.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.