Deleting blog posts the right way!

If you have a page of similar content then yes your fine to 301 the page you no longer need to the new page. 

This mostly matters if you have external links pointing to that page. If there are none then there is no advantage in having the redirect in place. 

If you plan on removing the page and want it gone quickly then you need to return a 410 error code when the page is accessed. This tells google the page has gone and is not coming page. Leaving it as a 404 (page not found) google will keep coming back for months checking if you have put the page back. 

Don't forget though if redirecting or removing a page to also remove any internal links to that page. You cant do a lot about external links but links on your own site should never be redirected or produce an error. This would not signal a well-managed site to Google.

A quick and dirty method to check for links is to put the URL in google search. Make sure you put the address within quotes so "mywebsite.com/123" 

if it returns no listings then you are safe to just delete the page. 

If you want to be 100% sure then you would need to use a backlink tool such as ahref (paid for version) This may be a bit of an overkill for what you're trying to do. 

I have not checked this out but your page title is 

Raleigh Newborn Photographer | Raleigh Newborn Photographer | Nicola Lane Photography

And I would imagine that was duplicated around your site. Word press uses the page title when you create the page and it has to be unique. If it's not unique it will add a number on the end, hence 28. I would guess you have made at least 28 pages with the exact same page title.

I am not a big user of word press but I am pretty sure they call this the slug, I believe you can change this to whatever you prefer, however, do bear in mind you are changing the URL so creating a different page by altering it. Any links going to the old URL will now produce a 404 error (page not found).

Changing the page title after the event though will not change the slug so you may look at pages with this number but now the page title does not match but did at the time of creating. 

I am sure some Wordpress expert will come along and give you a better answer but that's why I think you have the number tagged on the end. 

There are no fast options

Instead of deleting the posts you can update the blog with new data & publish it as an updated version blog. 

Go to your blog site and go there and go to settings or lay out option and delete your post

You can 301 redirect your old work to an existing work that matches your best work now or you can create new content on that page. But since you are saying that you have uploaded those images to several so it would be a good idea to update the existing content on your page and make another one.