onchain

So.. i dont know if its the place to post it but here goes:
- I mint an SVG onchain, which is base64 encoded
- Additionally you need to base64 encode it second time, with all the metadata
- OpenSea views it just fine
- Back at my app, if I want to view the SVG in its initial form, I need :
- Get the tokenId from the owner
- Get the tokenURI by tokenId
- Remove the metadata 
- Decode it once
- Remove some junk
- Decode it twice
- Then i get the SVG.

Somehow this seems excessive. How does opensea just get the image?