Where do I put the DLL files in an ASP.NET application

[esimsnl]

When I try to simply load a webp file into a bitmap, I get the error:

Unable to load DLL 'libwebp_x86.dll': The specified module could not be found. (Exception from HRESULT: 0x8007007E) In WebP.GetInfo In WebP.Load

I am using ASP.NET version 4.8 and so far I have placed DLL files in /bin folder. I also tried /bin/Release and / (root), but without success.