I tried with no configuration file and with different configuration files, none worked :

1. 

{
     "logo": {
        "type": "auto",
        "source": "/home/wololllooo/Images/ascii-art.txt",
        "width": 28,
        "height": 12
    }
}

2.

{
    "$schema": "https://github.com/fastfetch-cli/fastfetch/raw/dev/doc/json_schema.json",
     "logo": {
        "type": "auto",
        "source": "~/Images/ascii-art.txt",
        "width": 28,
        "height": 12
    }
}

3.
{
    "$schema": "https://github.com/fastfetch-cli/fastfetch/raw/dev/doc/json_schema.json",
     "logo": {
        "type": "auto",
        "source": "~/Images/ascii-art.txt",
        "width": 28,
        "height": 12
    },
    "display": {
        "separator": "  ",
        "constants": [
            "─────────────────" // {$1}, used in Custom module
        ],
        "key": {
            "type": "icon",
            "paddingLeft": 2
        }
    },
    "modules": [
        {
            "type": "custom", // HardwareStart
            // {#1} is equivalent to `\u001b[1m`. {#} is equivalent to `\u001b[m`
            "format": "┌{$1} {#1}Hardware Information{#} {$1}┐"
        },
        "host",
        "cpu",
        "gpu",
        "disk",
        "memory",
        "swap",
        "display",
        "brightness",
        "battery",
        "poweradapter",
        "bluetooth",
        "sound",
        "gamepad",
        {
            "type": "custom", // SoftwareStart
            "format": "├{$1} {#1}Software Information{#} {$1}┤"
        },
        {
            "type": "title",
            "keyIcon": "",
            "key": "Title", // Title module has no key by default, so that icon is not displayed
            "format": "{user-name}@{host-name}"
        },
        "os",
        "kernel",
        "lm",
        "de",
        "wm",
        "shell",
        "terminal",
        "terminalfont",
        "theme",
        "icons",
        "wallpaper",
        "packages",
        "uptime",
        "media",
        {
            "type": "localip",
            "compact": true
        },
        {
            "type": "publicip",
            "timeout": 1000
        },
        {
            "type": "wifi",
            "format": "{ssid}"
        },
        "locale",
        {
            "type": "custom", // InformationEnd
            "format": "└{$1}──────────────────────{$1}┘"
        },
        {
            "type": "colors",
            "paddingLeft": 2,
            "symbol": "circle"
        }
    ]
}