Image dimensions for various overworld sprites? [SOLVED]

So I got a bit of a problem. Right now, I'm trying to set it up so that there's a large wall of trash blocking the player's path. I know I can't put it as a tileset, because then it will always be there and there will be no way to get through it. So what I want to do is put it as an event and use it as a graphic on the overworld so that when a switch triggers, it'll disappear. Problem is that I don't know how big to make the actual image sheet so it will actually use the full graphic. Right now it's 145x145 pixels. Is there a formula to determine how to make it fit as a graphic or does anyone know what size the sheet should be?
Thanks for the help. Pic related is the trash I'm trying to use.

Why not putting it on the tileset graphic and then use it as tge events graphics? That way i already made a moving cupboard

Well, I already have it as a tileset. It's currently acting as a border for one of my towns, along with other trash. Is there a wiki page that describes what you're talking about? I haven't come across anything like that nor have I seen it in the tutorials I've been watching. Pic related is basically what I'm trying to do and where I'm trying to put it.

When you select the graphic for the event, on the very tope you can choose (None) and (Tileset). You would select tileset and then select the tile that contains your graphics. you create as many events as you need for the graphic

Wow, thanks for explaining that. I never noticed that little bit before. Just as a final note, this is the only way to really do it, right? Or am I missing a way to select more than one tile in this case? Really appreciate the help.

What do you mean by "select more than one tile"?
There probably is a different solution to that as well but nothing that i would know about ??????

I meant selecting a box like you can when you're using tilesets, to drop down a larger image. But this works for me. Thank you for the help!

I don't think that it works

Yeah, you're making this way more complicated than it needs to be lol. Just throw the entire trash pile into a new image in the graphics editor of your choice, and then multiply the width and height of the canvas by 4. This will format it like a regular rmxp characterset.

Then just make ONE event in the center of where it should be in the OW, and finally make a row of events that block the player until the remove it.

Wow, didn't know that was a thing. You're right, that makes it a whole lot easier. Thank you so much for the advice as well! Managed to get it working just fine in a 580x575 canvas.