PHP - If Link Exists Then Show Image

I apologize in advance for any misuse of terminology. I find that I am rather ignorant in such things.

I'm working on a WordPress theme. Specifically on the part that shows the "next: link-to-next-post" and "previous: link-to-prev-post" links.

Here is the code that I have:
Code: [Select]
<?php
  $nextvar=next_post_link('%link');
  $prevvar=previous_post_link('%link');
?>

<?php if (isset($nextvar)) { ?>
<h3>Next</h3>
<p><?php next_post_link('%link'); ?></p>
<? } ?>

<?php if (isset($prevvar)) { ?>
<h3>Previous</h3>
<p><?php previous_post_link('%link'); ?></p>
<? } ?>
The first part intends to check if the links exist. And this works fine.

However, the only output I'm getting are the values of $nextvar and $prevvar. The headers are nonexistent. What's wrong?

Any help is much appreciated, and I thank you in advance.

I am displaying rows from a database onto a page using:

while($row=mysql_fetch_array($query)){

echo $row['name'];

}

I need to figure out how to limit the rows shown to the page to 100. And if there are 100 rows on the page, a link will be displayed at the bottom, that says "Next 100". Then this will display the next 100 rows.
Can you give an example how to do this please?

Thanks

What is the best/proper way to check if a supplied URL goes to an actual image?  My site will allow users to enter an image URL (like "http://example.com/images/monkey.jpg").  I will store the URL they enter in a MySQL database and then will call it up later and do some resizing to these images. 

But I don't want to try to do any resizing if the URL they supply doesn't actually go to an image, or if it's blank (i.e. the user didn't enter a URL yet). 

So basically, I will run a MySql query to pull back the contents of the column called "imageurl".  Let's say those contents are stored in a variable called $imageurl.  This is what I'm trying to accomplish....

Code: [Select]
if ($theimageurl does NOT contain a URL to an image OR is blank) {
// do this
} else {
//run my resizing code
}
I guess i could do this to check to see if it's blank, but not sure this is proper/most efficient way to check that part of the issue...

Code: [Select]
if (trim($theimageurl) == "")
But greater than the "is it blank" concern is that people may enter URLs that just to a regular website so whether it's at this point in my code (or for security, I should probably do it BEFORE inserting it into my database :/ ) so curious if there are any functions that check to see if it's an image URL or not.  I know of file_exists, but I'm pretty sure that's just checking to see if a file exists and doesn't check image URLs.

Any info/suggestions would be appreciated as always! 

And if there are any recommended functions to check/clean the user-entered URL BEFORE it's entered into the database, please share

Thanks!

 
Please help before this script drives me insane.
It tries to download a skin from Minecraft.

It works fine, except, if it returns an error code, (301, 302, 404), don't download, and using my image (char.png) as a replacement.
I can get the error code, except, no matter how I compare it, it will a) still say it's 302 or b) not work at all.


Here's my code:

userskin.inc.php >
<?php
require('class.mineuser.php');
if(!isset($_GET['width']) || strlen(trim($_GET['width'])) == 0 || !isset($_GET['height']) || strlen(trim($_GET['height'])) == 0) {
$x = 16;
$y = 16;
} else {
$x = $_GET['width'];
$y = $_GET['height'];
}

if(isset($_GET['refresh'])) 
$refresh = true;
else
$refresh = false;

if(isset($_GET['debug'])) 
$debug = true;
else
$debug = false;

$http = curl_init("http://www.minecraft.net/skin/{$_GET['user']}.png");
curl_setopt($http, CURLOPT_RETURNTRANSFER, 1);
$result = curl_exec($http);
$http_status = curl_getinfo($http, CURLINFO_HTTP_CODE);
$resp = preg_match("/302/", $http_status, $match);
$code = $match[0];
if($code == 302) {
mineuser::downloadSkin($_GET['user'], $_GET['path'], $code, $refresh);
mineuser::getFace($_GET['user'].".png", $x, $y, $_GET['path'], $code, $debug);
} else {
mineuser::getFace("char.png", $x, $y, $_GET['path'], $code, $debug);
}

class.mineuser.php >
<?php
class mineuser {
public static function downloadSkin($user, $path = "", $resp, $new = false) {
if($resp !== 302) {
//Checks if $new is true, if it is, then delete $user.png and download a new one.
if($new == true) unlink("$path/$user.png");

//Checks if the users skin already exists (faster loading time)
if(!file_exists("$path/$user.png")) { 
$fh = fopen("$path/$user.png", "w"); 
$file = file("http://www.minecraft.net/skin/$user.png");

foreach($file as $char) //Since it's an array, we use a foreach loop and write each character individually
fwrite($fh, $char);

fclose($fh); //Close our file handler. 
}
} else {

}
} //End of function downloadSkin()

public static function getFace($user, $width, $height, $path, $resp, $debug = true) {
$im = imagecreatetruecolor($width, $height);
if($debug == false) {
header("Content-type: image/png");
}
if($resp === 302) {
$image = imagecreatefrompng("$path/char.png");
} else {
$image = imagecreatefrompng("$path/$user");
}
imagecopyresampled($im, $image, 0, 0, 8, 8, $width, $height, 8, 8);

imagepng($im);
imagedestroy($im);

} //End of function getFace()
}
?>


please help before i go insane 

Thanks in advance 

What is the best/proper way to run an image URL from an external site through a check to see if the image actually exists?   I am trying to use file_exists() but it's not recognizing image URLs from external sites as existing, so there must be some other way to deal with external URLs.   In other words, the image does exist but file_exists() says it doesn't.

Can anyone help?