Sprites artifacts with scaling

I'm trying to add sprites to my game, and there is a texture problem: depending on the sprites' size and/or the window scaling, pixels surrounding the sprite are sometimes drawn on screen.

As an example, here is the "eye" sprite, with its surrounding pixels:


But the in-game rendering sometimes trim pixels on a side, and sometimes add pixels from neighbour sprites

The BTerm is built like that:

```rust
let context = BTermBuilder::new()
.with_title("Roguelike Tutorial")
.with_tile_dimensions(16, 16)
.with_simple_console(80, 50, "16x16-sb-ascii.png")
.with_font("16x16-sb-ascii.png", 16, 16)
.with_sprite_console(16 * 80, 16 * 50, 0)
.with_sprite_sheet(
SpriteSheet::new("resources/MRMOTEXT_rexpaintx2.png")
.add_sprite(Rect::with_size(144, 352, 16, 16))
)
.with_vsync(false)
.build()?;
```

Both PNGs have 16x16px tiles/sprites. I tried different settings to fix this issue but to no avail.

Edit: same issue when the spritesheet is used as a font file: