I'm having this rule which works just fine:
RewriteRule ^([^/-]*)-([^/-]*)-([^/-]*)-([^/-]*)-([^/-]*)-([^/-]*)-([^/-]*)-([^/])*\.jpg$ $1.jpg [QSA]
It means 1-x-x-x-x...jpg will always be in first place of the rule. What I wanted to do is to have is x-x-x-x...1.jpg which means to make it last in this rule but I'm quite lost after hours of trying if this is possible at all.
With your shown samples and attempts, please try following htaccess rules. Please make sure to clear browser cache before testing your URLs. It just has 2 capturing groups, while rewriting mentioning 2nd group later to achieve shown samples name of jpeg.
RewriteEngine ON
RewriteRule ^([^-]*)-([^.]*)\.jpg/?$ $2-$1.jpg [QSA,L]
2nd solution: Either use above rules OR use following ones. This is based on your shown attempt which I have fixed here. You need not to mention / in your regex since its not present in .jpg file. Simply we are capturing all values in 8 groups and mentioning 1st group as last to make jpeg as x-x-x-x...1.jpg format mentioned by you in question.
RewriteEngine ON
RewriteRule ^([^-]*)-([^-]*)-([^-]*)-([^-]*)-([^-]*)-([^-]*)-([^-]*)-([^.])*\.jpg/?$ $2-$3-$4-$5-$6-$7-$8-$1.jpg [QSA,L]