@purpl3-yt You can use GL11.GL_QUADS to render an image, you just need to bind the image, in minecraft you bind the image like so mc.getTextureManager().bindTexture(new ResourceLocation("path to resource or image inside /assets/minecraft/"))
and render the quads like so:
GL11.glBegin(GL11.GL_QUADS);
GL11.glTexCoord(0, 0);
GL11.glVertex2d(x, y);
GL11.glTexCoord(1, 0);
GL11.glVertex2d(x2, y);
GL11.glTexCoord(1, 1);
GL11.glVertex2d(x2, y2);
GL11.glTexCoord(0, 1);
GL11.glVertex2d(x, y2);
GL11.glEnd();