Recognize encoding method

Question

Programming

[icon_url] => Vfjo9hWxf_QlLQ6_qg_U6-20IkdRwXG68OmatxT_iUSN8dgHSa0vrYK1HAGXb45z_e83Rxudceugt5unAeqbXJH78FAI-TO71vQbXoZ_nSi082YAX9dq7qGw
[icon_url_large] => Dc9VGES8yNiBKkzPArtj5LWDn6kAzMaWVO7Yx7xLPkvVxmXpGKCYgSayXnE_2zl8pdiKqUqQxscEsNncrU87Q9eHePwN-oiSdO4DaX3Nai3owA==

At first glance, the links are encoded in base64, but they are not. Help identify the algorithm.

Answer 1

Answer: It turned out that there was no need to decrypt it, it turned out to be just part of the link
cdn.steamcommunity.com/economy/image/Vfjo9hWxf_QlLQ6_qg_U6-20IkdRwXG68OmatxT_iUSN8dgHSa0vrYK1HAGXb45z_e83Rxudceugt5unAeqbXJH78FAI-TO71vQbXoqY9

Answer 2

I use the following algorithm: I encode the string in base64, then I use two strings with mixed characters A-Za-z0-9+/=. In the encoded string, I replace the characters from the first string with the corresponding position in the second string. The algorithm is simple, maybe there is something similar.
There are no _- characters in base64, usually -_~ instead of +/= is used for transmission in http requests. Judging by the lines, only + and / were replaced there.