I got 3 different ancient coins and don't know much about them. [solved]

I got the three different ones from left to right, obverse, and reverse from top to bottom. 

Hello and welcome to Numista!

Please download the picture from Discord then upload to this post. It's much too small to see anything. Also, please post diameter and weight for each coin and best guess at composition.

Can't you right click and “Open in a new tab” then it should be large.

I can obviously since I knew it was a hot link to Discord.   Many members can't or won't.

Did I fix it?

Sort of. 

The image is just about usable but the advice to include diameter, and weight when you have it is good advice, it often is necessary.

You have a tetradrachm of Philip I, struck at Antioch, there are a lot of possibilities in terms of catalog number but here is a starting point for a search if you are inclined to take it further:

https://rpc.ashmus.ox.ac.uk/search/browse?volume_id=&number=&city_id=25&province_id=&subprovince_id=&issue_id=&reign_id=15&obverse_inscription_simplified=&reverse_inscription_simplified=%CE%91%CE%9D%CE%A4%CE%99%CE%9F%CE%A7%CE%99%CE%91&obverse_design=radiate&reverse_design=&metal_id=&weight_min=&weight_max=&diameter_min=&diameter_max=&format=

The second is an antoninianus of Postumus, MONETA AVG, Moneta with scales and cornucopia.

The third is Constantine I, reverse is upside down, IMP CONSTANTINVS PF INV AVG,  IOVI CONS-ERVATORI, Jupiter holding a Victory on globe and sceptre, with an eagle at his feet.  Looks like the mint is Thessalonica but the image is too poor for me to be able to isolate the mintmark to say any more.

(sorry double post when trying to edit the link above, it had been somehow automatically edited by the forum software to break the link).

Purplexed

The image is just about usable but the advice to include diameter, and weight when you have it is good advice, it often is necessary.

 

You have a tetradrachm of Philip I, struck at Antioch, there are a lot of possibilities in terms of catalog number but here is a starting point for a search if you are inclined to take it further:

https://rpc.ashmus.ox.ac.uk/search/browse?volume_id=&number=&city_id=25&province_id=&subprovince_id=&issue_id=&reign_id=15&obverse_inscription_simplified=&reverse_inscription_simplified=%CE%91%CE%9D%CE%A4%CE%99%CE%9F%CE%A7%CE%99%CE%91&obverse_design=radiate&reverse_design=&metal_id=&weight_min=&weight_max=&diameter_min=&diameter_max=&format=

 

The second is an antoninianus of Postumus, MONETA AVG, Moneta with scales and cornucopia.

 

The third is Constantine I, reverse is upside down, IMP CONSTANTINVS PF INV AVG,  IOVI CONS-ERVATORI, Jupiter holding a Victory on globe and sceptre, with an eagle at his feet.  Looks like the mint is Thessalonica but the image is too poor for me to be able to isolate the mintmark to say any more.

Thanks!