If I get 0,5 ml Juvederm, will it be visible? (Photo)

Thank you for sharing your question and photograph.  Unfortunately without an in-person discussion as to your goal results it is difficult to offer definite advice, but due to the lip tendency of swelling, I would recommend an initial 0.5cc treatment of your lips while then allowing your results 2 weeks time to mature.  If at that time you want additional volume, go back serially until you have achieved your desired outcome.  Hope this helps.

If you're looking to inject just the upper lip, as I would based on your picture, a 0.5cc amount is likely a great starting point. If planning to do the entire lips, then go for a full 1cc syringe. More importantly, have an expert who knows lip anatomy injecting you (e.g. dermatologist) for optimal results & fewest possible side effects and least downtime.

It depends on your expectations.  1 cc of filler is 1/5 of a teaspoon, so a fairly small volume.  You will see an increase in volume with 0.5 cc filler. If you are unsure I would get less and wait 2 weeks for swelling to fully go away and add more if you want more at that time.

It depends on the look you are trying to achieve. You have nice shaped lips to begin with so it depends on how much fullness you are trying to achieve. I would recommend you start with 0.5ml and then wait two week for swelling to resolve and if you desire a fuller look then you can always add more. 

The answer will depend on your goals for treatment.  If you are wanting a conservative improvement in fullness, then you should notice a difference with 0.5 ml.  With 1ml there would be a more noticeable change.  The wonderful thing about fillers is that you can go slowly.  If you try 0.5ml and find it isn't enough, you can always return for more.  Please note that swelling is common with lip injections so it's recommended that you wait 2 weeks after treatment before considering further injections.