1. Designed by her, the bag is popular these days.

1-2. Being designed by her, the bag is popular these days.

2. Because it was designed by her, the bag is popular these days.

3. Because the bag was designed by her, it is popular these days.
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Can #1 be changed either #2 or #3? Are they all the same? Between #2 and #3, which one is commonly used? What about #1-2? Is this expression good?

1-2, 2, and 3 all seem to mean the same thing. #1 does not mean exactly the same thing. It means that the popular bag was designed by "her". The others suggest that the bag is popular BECAUSE it was designed by "her" (a famous designer whose designs are always popular?).