How to edit the sprites of Land Protector, Poem of Bragi, Safety Wall, Sanctuary, etc?

[Lidatum]

I've seen grf with custom sprites for those skills. Can anyone tell me how to edit them? Where can I find the skill sprites in data.grf? I can't seem to find them in data/sprite and in data/texture/effect

Thanks.

Edited October 7, 2017 by Lidatum

[sader1992]

search about .str files and str editor

[Lidatum]

1 hour ago, sader1992 said:

search about .str files and str editor

I know about str files and str editor. There are str files for safetywall and sanctuary, but they only cover the animation when the skills are casted (safeline.bmp for safetywall, and some angel sprites for sanctuary). They don't change the safetywall and sanctuary on the ground.

Does anyone know a link to a custom grf with edited Land Protector, Loki's Veil, etc?