Double "и" is pronounced just as two "и" vowels: ee-ee.
Whenever you see a combination of vowel letters in Russian, just pronounce each sound as it is. Russian is not like English. In English a combination of vowels is not the same as two separate vowels, e.g. "au" is not just "ay"+"you" but a completely new vowel, right? But Russian is much simpler in this regard. Just read each vowel as its own sound.
Unfortunately, I cannot see your attachmentjust an error notification...
However, I can guess what you mean. Is it like a high soft sign (Ь) with a strikethrough on the top of it? If yes, it is an old letter (it's name is ЯТЬ) which was in use until 1918. You can still find it in some old texts. Its pronunciation is exactly the same as the pronunciation of Е. So, the schoolchildren had to memorize in those times, where to write the plain Е, and where to write ЯТЬ. The spelling was much more complicated for them.