[Graphic✓] Changing the offset used for a sprite

Apologies if this has been asked before - I've been looking for a solution for awhile, but I'm a total beginner so I'm not really sure what I'm even looking for. I'm using Fire Red 1.0.

I changed the rival's intro sprite, and NSE automatically repointed it when I saved since it was too big (from 0x4623EC to 0x71A37C, if that's important). So I know where the sprite is stored, I just need to figure out how to change the offset so that it shows up correctly in-game.

I've been looking around XSE and HxD, but I have no idea what I'm doing. I also can't find the sprite in unLZ. Any help would be appreciated!

Edit: I did it! I'll explain what I did for anyone having the same problem.

1. Found the sprite in unLZ (number 343) with help from >Dante<'s Intro Hero tutorial.
2. Imported the new .bmp sprite that I'd previously exported from NSE
3. Clicked "write to ROM", and checked all boxes except for "Export Palette".
4. Wrote the new offset in the Image Offset field (0071A37C).

And that was it!

What I would do, is search for information online about the intro sequence.
Possibly there are good threads telling you where the script is for the intro.
Find out how the script works itself, and the part which points to the sprite to display.
Then you can change the offset to the one for your new sprite, and save the edited script.
Sorry if this is already obvious to you and you just want the location of the script, I don't know it because I have not done that part yet myself.

Now I see your solution, it's good. It answers for me how to change some sprites myself that I wanted to.

(possible misunderstandings, poor knowledge of English)
I'll tell you a little about the displacements in HxD, first unlz contains the window (Write in ROM) there is the address (image of the address), copy it and look in HxD with the hot ctrl + g combination, usually the first four bytes of 10 00 08 00, and so on. this is the format (the title of the images) .and then the memory is filling up the image of the image. The game itself refers to a link that will subsequently indicate our image. How to find the link to Example 00 71 A3 7C, we need to find the return address by the formula AB CD EF-> ef cd ab and add 08 (you might have thought 00, but no)
the 08 digit means that the information will be downloaded in ROM.00 in BIOS 07 in oam
, by the way, if we had the address 01 00 00 00. this would be 00 00 00 09 (01-> 09).
find the reverse pointer HxD ctrl + f -> hex value and look for 7c a3 71 08 (search directon all) you went where you need, you can change 4 bytes to any address here. And by the way you are at the end of the executable, part of the program , usually the structure of the program ends with the output of memory in the cell, just where we are