Question about sitewide links and image links

I just wanted to get some opinions on two different types of links -

1.Sitewide links - I know generally these type of links are not a good idea any more because they can be a bit spammy, but what are your thoughts?

2.Image links - same question, how much difference is there in power between a contextual link or a link using some anchor text and an image link (Aside from that fact that its not targeting a specific keyword, just talking purely about the power of the link itself.

I have a couple of links that fall into the above categories and they are from sites that are very authoritative - probably some of the most authoritative sites I can get links from within my niche, but obviously the other characteristics of these links are not great (ie they are sitewide and not contextual).

What are your thoughts about this?

Yeah few of them would like to use sitewide links because for their categories they want to get some visitors apart from building links to the inner pages. But they can see the effects by the sitewide links.

Image links are more effective compared to contextual links. For an example, infographic links and other kind of image links gives good results.

IMO, Compared to sitewide links Image links would be effective.

Sitewide is really a hit an miss... You need them from relevance authority website, with brand anchor text to get the huge link juice. Other than that, its value will be diminished significantly

For image links can't really comment, but I believe they must be weaker than contexual backlinls

Thanks guys for the feedback.

Avoid sitewide, use everything else for diversity.