You’ll need to use an attributed string and add the image as instance of NSTextAttachment
:
NSMutableAttributedString *attributedString = [[NSMutableAttributedString alloc] initWithString:@"like after"];
NSTextAttachment *textAttachment = [[NSTextAttachment alloc] init];
textAttachment.image = [UIImage imageNamed:@"whatever.png"];
NSAttributedString *attrStringWithImage = [NSAttributedString attributedStringWithAttachment:textAttachment];
[attributedString replaceCharactersInRange:NSMakeRange(4, 1) withAttributedString:attrStringWithImage];