Question About Changing From ".gif" To ".jpg"

Volitics

I'm working on a file upload script. I've got the script designed so that it will accept images with the following suffixes: .gif, .jpg, and .bmp.

I've got the script written so that it replaces the names of the image with a number. The first image that is uploaded has the number "1", the second image uploaded has the number "2", and so forth.

The script works fine if the user uses the image upload page just once. A problem might occur, though, if the user hit back button, returned to the file upload form, and uploaded more images.

If there is an image in the folder on the server named "1.gif" and if the additional image that the user uploads is a ".jpg" image then the image might be "1.jpg". In other words, both images would have the prefix "1" - but both images would have a different suffix. That may cause difficulties later on.

I think that I may already have a solution to the problem. What I can do is use one of the string functions and replace the ".gif" and ".bmp" suffixes with the ".jpg" suffix on each image. That way all of the images would have the same suffix.

As a test, I've manually changed the suffixes on all of the images in a folder to the ".jpg" suffix. The images seem to be working ok. However, I wonder if I might be overlooking something.

I know that the ".gif", ".jpg", and ".bmp" images are different. The file sizes are different in the folder.

Does anyone know any reason that changing the image suffixes to the ".jpg" suffix would cause any problems?

Thanks.

Volitics

GreyBoy

From a graphix stand point, I dont know what kind of imgs you are referring to, but lets say someone has a transparent gif, if it is changed to a jpg, it will no longer be transparent. Is that what you where referring to or where you referring to it from a coding stand point???

Jeb_

Originally posted by Volitics
The script works fine if the user uses the image upload page just once. A problem might occur, though, if the user hit back button, returned to the file upload form, and uploaded more images.

If there is an image in the folder on the server named "1.gif" and if the additional image that the user uploads is a ".jpg" image then the image might be "1.jpg". In other words, both images would have the prefix "1" - but both images would have a different suffix. That may cause difficulties later on.

I think that I may already have a solution to the problem. What I can do is use one of the string functions and replace the ".gif" and ".bmp" suffixes with the ".jpg" suffix on each image. That way all of the images would have the same suffix.

Why don't you compare the I.D. numbers instead of the number and extension? Just increment the ID by one for every image uploaded - regardless of filetype.

Weedpacket

Especially if you're going to end up with giving .bmp or .gif images a .jpg file extension. That's just silly.

And what about .png? And who uses .bmps?

goldbug

mmmmmm PNG

preemptive: mmmm SVG

Volitics

This is what I prefer to do:

Why don't you compare the I.D. numbers instead of the number and extension? Just increment the ID by one for every image uploaded - regardless of filetype.

In order to do this would I incorporate the "imagepng()" function into my script?

Volitics

Elizabeth

Agree with the ID numbers comparison- another point to mention besides the transparent gif's are the animated gifs will no longer work when switched to jpg.

Jeb_

Originally posted by Volitics
In order to do this would I incorporate the "imagepng()" function into my script?

No, you won't need that function. That function outputs a new PNG image. You just want to add the uploaded image in sequence with everything else without changing the extension, but without getting any duplicates - right?

All you need to do is find the ID of the last image that was uploaded. Add 1 to that value. Use that as the filename for the new image - keeping the extension on the end.

// psuedo-code follows

// might be "16" for example
$oldID = get ID of last image uploaded.

// gives something like "17.jpg"
$newfilename = ($oldID+1) . '.' . $image_ext;

copy_image($new_filename);

Volitics

Jeb,

Thank you for the help.

I'll start working on it.

Thanks again.

Volitics

Jeb_

You're welcome. Give us a yell if you run into strife.