forgejo/templates/repo/issue/view_content/attachments.tmpl

<div class="dropzone-attachments">
	{{if .Attachments}}
		<div class="ui clearing divider"></div>
	{{end}}
	<div class="ui middle aligned padded grid">
		{{$hasThumbnails := false}}
		{{- range .Attachments -}}
			<div class="twelve wide column" style="padding: 6px;">
				<a target="_blank" rel="noopener noreferrer" href="{{.DownloadURL}}" title='{{$.ctx.i18n.Tr "repo.issues.attachment.open_tab" .Name}}'>
					{{if FilenameIsImage .Name}}
						{{if not (containGeneric $.Content .UUID)}}
							{{$hasThumbnails = true}}
						{{end}}
						<span class="ui image">{{svg "octicon-file"}}</span>
					{{else}}
						<span class="ui image">{{svg "octicon-desktop-download"}}</span>
					{{end}}
					<span><strong>{{.Name}}</strong></span>
				</a>
			</div>
			<div class="four wide column" style="padding: 0px;">
				<span class="ui text grey right">{{.Size | FileSize}}</span>
			</div>
		{{end -}}
	</div>

	{{if $hasThumbnails}}
		<div class="ui clearing divider"></div>
		<div class="ui small images thumbnails">
			{{- range .Attachments -}}
				{{if FilenameIsImage .Name}}
					{{if not (containGeneric $.Content .UUID)}}
					<a target="_blank" rel="noopener noreferrer" href="{{.DownloadURL}}">
						<img class="ui image" src="{{.DownloadURL}}" title='{{$.ctx.i18n.Tr "repo.issues.attachment.open_tab" .Name}}'>
					</a>
					{{end}}
				{{end}}
			{{end -}}
		</div>
	{{end}}

</div>