Size and weight are big decision factors when you are trying to find the ideal camera for your needs.
In this section, we are going to illustrate the Olympus E-PM1 and Olympus VR-340 side-by-side from the front, back and top in their relative dimensions. Olympus E-PM1 has external dimensions of 110 x 64 x 34 mm (4.33 x 2.52 x 1.34″) and weighs 265 g (0.58 lb / 9.35 oz) (including batteries). Olympus VR-340 has external dimensions of 96 x 57 x 19 mm (3.78 x 2.24 x 0.75″) and weighs 125 g (0.28 lb / 4.41 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-PM1 and the Olympus VR-340. Olympus VR-340 is clearly the smaller of the two cameras. Its body is 14mm narrower, 7mm shorter and 15mm thinner than Olympus E-PM1. As you can tell, actually this is not a fair size comparison since Olympus VR-340 has a built-in lens but Olympus E-PM1 doesn't. Once you put a lens on E-PM1, its thickness will increase significantly.
Now lets look at the top view comparison of Olympus E-PM1 and Olympus VR-340.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Olympus VR-340 is significantly lighter (140g ) than the Olympus E-PM1 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 E-PM1, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Olympus PEN E-PM1 nor Olympus VR-340 provides any type of weather sealing in their bodies, 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 Mirrorless Cameras with Weather Sealing Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Olympus E-PM1 and Olympus VR-340's LCD screens have the same diagonal size of 3.00 inches.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.