Your post title says "text", your post above says "email", so I am assuming you've set up
Blue Iris to text your iPhone via SMTP (e-mail).
If you're texting the image via e-mail (SMTP), be use to use the correct e-mail address format for Boost Mobile's MMS service (
10digitmobilenumber@myboostmobile.com ) and
not their SMS service (
10digitmobilenumber@sms.myboostmobile.com).
This is because you cannot send/attach an image via SMS (regular text). This is also true of AT&T.