Mountain View, Calif. -- Eye-Fi, a Mountain View-based maker of wireless memory cards, said on Wednesday it has raised $20 million in its fourth round of funding, led by Japanese mobile operator NTT Docomo. Previous backers Shasta Ventures, Opus Capital and TransLink Capital also participated. The investment by NTT Docomo is part of a larger partnership with the company, which in April will launch Eye-Fi card activation through mobile phones. The deal means that NTT Docomo's 59 million mobile subscribers will be able to share high-quality images between their digital cameras, mobile devices, online photo sites and digital photo frame, without the need for a computer. Eye-Fi said it also has expanded its executive team, adding former Skype and eBay executive Michele Don Durbin as its vice president of marketing.