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 Canon ELPH 100 HS and Canon ELPH 340 HS side-by-side from the front, back and top in their relative dimensions. Canon ELPH 100 HS has external dimensions of 93 x 56 x 20 mm (3.66 x 2.2 x 0.79″) and weighs 140 g (0.31 lb / 4.94 oz) (including batteries). Canon ELPH 340 HS has external dimensions of 100 x 58 x 22 mm (3.93 x 2.27 x 0.88″) and weighs 147 g (0.32 lb / 5.19 oz) (including batteries).
Below you can see the front view size comparison of Canon ELPH 100 HS and Canon ELPH 340 HS. Canon ELPH 100 HS is clearly the smaller of the two cameras. Its body is 7mm narrower, 2mm shorter and 2mm thinner than Canon ELPH 340 HS.
Here is the back view size comparison of Canon ELPH 100 HS and Canon ELPH 340 HS.
Now lets look at the top view comparison of Canon ELPH 100 HS and Canon ELPH 340 HS.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Canon ELPH 100 HS is 7g lighter than the Canon ELPH 340 HS but we don't think this will make a significant difference.
Unfortunately neither Canon ELPH 100 HS (IXUS 115 HS) nor Canon PowerShot ELPH 340 HS (IXUS 265 HS) 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 Compact Cameras with Weather Sealing
LCD Screen Size and Features
Canon ELPH 100 HS and Canon ELPH 340 HS'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.