Cryptic crossword No 2,503

Across

1. Images set inside composition becoming reactive to light  (15)
2. A calcium oxide clay mixed with any tar is good for the gut (10,5)
3. Suitable alternatives to carpet? (3)
4. Ideas dealt with separately (5)
5. Bright revolutionary Russian lady attracted to west (5)
6. Tend to swallow nothing before politician gets to make an analogy (7)
7. Dock tails of yellow fish after removing fins to start with (5)
8. Inert caramel mixture found in tin from Costa Rica, possibly (7,8)
9. Chuck down dictator's harness for common pets (4,4,3,4)
10. Counting frames in a beat clip skipping every other one (5)
11. Toy that's somewhat repugnant (3)
12. Stream virulent broadcast after name is redacted (7)

Down

1. US foreign office said 'pert' meant 'wobbly'! (5,10)
2. They dry in broadcast with trophy committees (6,9)
3. Alternative energy coming from mineral source (3)
4. Middle remains audible (5)
5. A bit of yoga in Fulham could be worthwhile (7)
6. Sail exported from Djibouti (3)
7. Boost union's leader with compliments (7)
8. Passing on dash of brandy in glass (5)
9. Currency prices are soft? (5,2,8)
10. Mop the alien ship in a sloppy manner? That's wicked! (15)
11. Start to become firmer at home (3,2)
12. Embed crooked nail successfully in the end (5)