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 Panasonic ZS7 and Panasonic S3 side-by-side from the front, back and top in their relative dimensions. Panasonic ZS7 has external dimensions of 103 x 60 x 33 mm (4.06 x 2.36 x 1.3″) and weighs 218 g (0.48 lb / 7.69 oz) (including batteries). Panasonic S3 has external dimensions of 99 x 59 x 21 mm (3.9 x 2.32 x 0.83″) and weighs 117 g (0.26 lb / 4.13 oz) (including batteries).
Below you can see the front view size comparison of Panasonic ZS7 and Panasonic S3. Panasonic S3 is clearly the smaller of the two cameras. Its body is 4mm narrower, 1mm shorter and 12mm thinner than Panasonic ZS7.
Here is the back view size comparison of Panasonic ZS7 and Panasonic S3.
Now lets look at the top view comparison of Panasonic ZS7 and Panasonic S3.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Panasonic S3 is significantly lighter (101g ) than the Panasonic ZS7 which may become a big advantage especially on long walking trips.
Unfortunately neither Panasonic Lumix DMC-ZS7 (Lumix DMC-TZ10) nor Panasonic Lumix DMC-S3 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
Panasonic ZS7's 3" LCD screen is slightly larger than Panasonic S3's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.