I have written some tags in PHP as
<a href="<?php bloginfo('url'); ?>/?cat=<?php $cate_id ?>"><?php echo $resid->post_content ?></a>
or even this one
echo "<li><a href = '?cat=$cate_id'>".$resid->post_content."</a></li>";?>
Does this in any case affect the performance on the live server. I am no getting the image to appear on the live server after upload but on my local system(on my side) , things are fine..
The most likely issue is that the path to the image isn't right on the server. To check this, view the source of the page and look at the src attribute of the image and see if that path exists on your server by putting in the address bar.
No, tags never affect the server's performance. please make sure that when you use some framework may affect the code execution time.
No, jumping in and out of PHP should not affect anything in terms of server performance. Be sure to check your file path for that image that isn't rendering. It could be that the path is coded incorrectly or if you transfered the DB from local to live there may be local path settings that are incorrect.
I'd suggest opening the page in Firefox and clicking Tools -> View Page Info -> Media and anything grayed/italicized will be returning a 404.