Link your custom godaddy domain to your blogspot account.

If you purchased custom domain in godaddy have to link your custom domain(pics.com) to blogspot account(pics.blospot.com).

1.Please login into your blogspot account goto settings > basic > published tab > click the setup third party account.

2.Enter your custom domain name like "www.pics.com" without omitting "www" as below screenshot.

3.click save you will get an error sayings " we have not been able to verify authority of your domain".

Please take this screenshot for your future reference as shown in below.
Please note the highlighted details in your screenshot.

3.Login into your godaddy account, goto my products > IN domains (select manage) > Additional setting or find the "manage DNS" options > select manage DNS

Domain records list will show here,

4.check CNAME record is there if available try to edit the record 
Add below details its default for google blogspot accounts.

Hostname :  www
Point to   : ghs.google.com
TTL     :1 hour

 5.Click ADD one more CNAME options points to your blog.

    hostname :  copy the hostname  you taken screenshot from  blogspot in 3 rd step
    Point to   : copy the point to link you taken screenshot from  blogspot in 3 rd step
    TTL : 1hours

6.Here you need to add 4 IP addresses which are common for all the blogger users at the same record table shown above.

Click on "ADD" >> In "Type" choose "A" >> in "Host" type "@" >> and in "Points to" field type "216.239.32.21" As shown below;

Again as same as above, including all add following 4 address;
216.239.32.21
216.239.34.21
216.239.36.21
216.239.38.21

 Now domain record show below,

Once you completed all the above steps, then its time to save all the settings and publish the blog.

Again  goto blogspot settings > basic > published tab > save it ,Wait for 1 hours to process your request.