@JEHER_SINGH said:
api key not working my api key is not working for fetching poster.
error shows everytime, I try to fetch something

I don't know if that's what you're asking for, but ...

When an API Request is made, in the responses received you will find the Path of the images:
poster_path or backdrop_path or profile_path or logo_path or still_path.
Something like that:

backdrop_path   "/hZkgoQYus5vegHoetLkCJzb17zJ.jpg"   
poster_path "/r3pPehX4ik8NLYPpbDRAh0YRtMb.jpg"    

To access/download the image use the basic images URL.

https://image.tmdb.org/t/p/  

The request should be similar to these:

https://image.tmdb.org/t/p/[size]/[poster_path]  
https://image.tmdb.org/t/p/original/wigZBAmNrIhxp2FNGOROUAeHvdh.jpg  
https://image.tmdb.org/t/p/w500/wigZBAmNrIhxp2FNGOROUAeHvdh.jpg  

https://image.tmdb.org/t/p/original/wigZBAmNrIhxp2FNGOROUAeHvdh.jpg

Make sure to read the documentation around images.
https://developer.themoviedb.org/docs/image-basics
https://developer.themoviedb.org/reference/configuration-details
Image Sizes

https://api.themoviedb.org/3/configuration?api_key=THE_KEY