どうして画像が表示されないのでしょうか

html
1<!DOCTYPE html>
2<html lang="en">
3<head>
4	<meta charset="utf-8">
5	<meta name="viewport" content="width=device-width, initial-scale=1">
6	<title>Complete Bootstrap 4 Website Layout</title>
7	<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/css/bootstrap.min.css">
8	<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
9	<script src="https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js"></script>
10	<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js"></script>
11	<script src="https://use.fontawesome.com/releases/v5.0.8/js/all.js"></script>
12	<link href="style.css" rel="stylesheet">
13</head>
14<body>
15
16<!-- Navigation -->
17<nav class="navbar navbar-expand-md navbar-light bg-light sticky-top">
18	<div class="container-fluid">
19		<a href="#" class="navbar-brand"><img src="img/logo.png" alt=""></a>
20		<button class="navbar-toggler" type="button" data-toggle="collapase" data-target="#navbarResponsive">
21			<span class="navbar-toggler-icon"></span>
22		</button>
23		<div class="collapsa navbar-collapse" id="navbarResponsive">
24			<ul class="navbar-nav ml-auto">
25				<li class="nav-item">
26					<a href="#" class="nav-link">Home</a>
27				</li>
28				<li class="nav-item">
29					<a href="#" class="nav-link">About</a>
30				</li>
31				<li class="nav-item">
32					<a href="#" class="nav-link">Services</a>
33				</li>
34				<li class="nav-item">
35					<a href="#" class="nav-link">Team</a>
36				</li>
37				<li class="nav-item">
38					<a href="#" class="nav-link">Connect</a>
39				</li>
40			</ul>
41		</div>
42	</div>
43</nav>
44
45<!--- Image Slider -->
46<div id="slides" class="carousel slide" data-ride="carousel">
47	<ul class="carousel-indicators">
48		<li data-target="#slides" data-slide-to="0" class="active"></li>
49		<li data-target="#slides" data-slide-to="1"></li>
50		<li data-target="#slides" data-slide-to="2"></li>
51	</ul>
52	<div class="carousel-inner">
53		<div class="carousel-item">
54			<img src="img/background.png" alt="背景画像1">
55			<div class="carousel-caption">
56				<h1 class="display-2">Bootstrap</h1>
57				<h3>Complete website Layout</h3>
58			</div>
59		</div>
60		<div class="carousel-item">
61			<img src="img/background.png2" alt="背景画像2">
62		</div>
63		<div class="carousel-item">
64			<img src="img/background.png3" alt="背景画像3">
65		</div>
66	</div>
67</div>
68
69<!--- Jumbotron -->
70
71
72<!--- Welcome Section -->
73
74
75<!--- Three Column Section -->
76
77
78<!--- Two Column Section -->
79
80
81<!--- Fixed background -->
82
83
84<!--- Emoji Section -->
85
86  
87<!--- Meet the team -->
88
89
90<!--- Cards -->
91
92
93<!--- Two Column Section -->
94
95
96<!--- Connect -->
97
98
99<!--- Footer -->
100
101
102
103
104</body>
105</html>
106
107
108
109
110
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112
113
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116
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119
120
121 <!--- Check out w3newbie Templates & Courses! -->
122<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css">
123 <div style="float:left; max-width: 48%; margin: .5rem; padding: 0; border: .5rem solid #666;">
124 	<a href="https://w3newbie.com/templates/" target="_blank" style="z-index: 100; cursor: pointer!important;"><img src="https://www.w3newbie.com/wp-content/uploads/w3newbie-templates-zip.png" style="max-width: 100%; min-width: 100%;"></a>
125</div>
126 <div style="float:left; max-width: 48%; margin: .5rem; padding: 0; border: .5rem solid #666;">
127 	<a href="https://w3newbie.com/courses/" target="_blank" style="z-index: 100; cursor: pointer!important;"><img src="https://www.w3newbie.com/wp-content/uploads/w3newbie-courses-zip.png" style="max-width: 100%; min-width: 100%;"></a>
128</div>
129<br style="clear: both;">
130<div style="max-width: 52%; margin: 2rem auto; padding: 0; border: .5rem solid #666;">
131 	<a href="https://w3newbie.com/hosting/" target="_blank" style="z-index: 100; cursor: pointer!important;"><img src="https://www.w3newbie.com/wp-content/uploads/web-hosting-zip.jpg" style="max-width: 100%; min-width: 100%;"></a>
132</div>
133 <!--- Check out w3newbie Templates & Courses! -->
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