Hello ??
I interpret your question in two manners. So, let’s get to both of them.
1: Attachment pages
Is the report about the attachment pages, like example.com/img_raccoon_family?
I performed a manual inspection, and the page titles show up perfectly.
Aside from that, attachment pages shouldn’t be indexed — they’re low-quality, low-density, and low-context content and can bring your whole site down in ranking.
I see that all attachment pages are blocked from indexing, this is good because of the reason above.
I suggest activating the free Origin extension for extra conformity.
If the report from RavenTools was about this, then it’s a false-positive.
2: Inline images
If your querying about the inline image titles, then I’m afraid this is a WordPress issue. The Attachment SEO settings do not affect the embedded attachment titles; they only affect the attachment pages.
You can set titles by clicking on an image in the Media Library; you’ll find the field on the right-hand side.
Then, to resolve this, you need to reinsert the images on each applicable page.
Alternatively, you can go by every <img.. /> tag inserted on your pages via the “Text editor”, and insert alt tags manually.
Both routes are very time consuming, and I advise not to take them for the sake of your sanity.
To conclude
This isn’t a big issue. Nowadays, Google parses (most) images via their image interpretation algorithms.
This is much like Facebook’s DeepMask does for your Facebook photos (“like” a baby photo today and you’ll only see babies on Facebook tomorrow). So, your images are categorized automatically.
For example: if you right-click on one of your images in Google Chrome, and select “Search Google for Image”, Google will likely tell you the name of the pest, or at least the category.
