Blog assets being deleted even when in use

Hi Drew,

I guess the title explains it all - I've run force update, but it's continued to happen since.

Here's my diganostic:

Perch: 2.8.6
Production mode: (PERCH_PRODUCTION)
Installed apps: content (2.8.6), assets (2.8.6), categories (2.8.6), perch_blog (4.6), perch_forms (1.8.3), perch_backup (1.2), perch_twitter (3.5.1)
DB driver: PDO
DB tables: perch2_blog_authors, perch2_blog_comments, perch2_blog_index, perch2_blog_posts, perch2_blog_posts_to_tags, perch2_blog_sections, perch2_blog_tags, perch2_categories, perch2_category_counts, perch2_category_sets, perch2_content_index, perch2_content_items, perch2_content_regions, perch2_forms, perch2_forms_responses, perch2_navigation, perch2_navigation_pages, perch2_page_templates, perch2_pages, perch2_resource_log, perch2_resource_tags, perch2_resources, perch2_resources_to_tags, perch2_settings, perch2_twitter_scheduled_tweets, perch2_twitter_settings, perch2_twitter_tweets, perch2_user_privileges, perch2_user_role_privileges, perch2_user_roles, perch2_users
Users: 18
App runtimes:
<?php
    $apps_list = array(
        'content', 
        'categories',
    'perch_twitter',
    'perch_forms',
    'perch_blog'
    );
Scheduled tasks for perch_twitter: post_tweets (1 mins)
Scheduled tasks for perch_blog: delete_spam_comments (1440 mins)
Editor plug-ins: redactor, markitup
H1: b0b34191ed87c03fc0ba8c4efe6fe8bd
L1: a837757d008b9f82775159c0eb1862b8
headerColour: #ffffff
content_singlePageEdit: 1
helpURL: https://experiencewalesinvenice.org/docs
siteURL: https://experiencewalesinvenice.org
hideBranding: 1
content_collapseList: 1
lang: en-gb
update_2.8.4: done
latest_version: 2.8
on_sale_version: 2.8.7
headerScheme: light
dashboard: 0
hide_pwd_reset: 0
content_hideNonEditableRegions: 0
content_frontend_edit: 1
logoPath: /perch/resources/logo-partner-ff.png
perch_twitter_update: 3.5
perch_blog_update: 5.0
perch_blog_post_url: /blog/{postSlug}
update_2.8.6: done
perch_blog_slug_format: %Y-%m-%d-{postTitle}
perch_blog_akismet_key:
perch_blog_max_spam_days: 0
perch_backup_mysqldump_path:
perch_blog_comment_notify: 0
PERCH_DEVELOPMENT: 10
PERCH_STAGING: 50
PERCH_PRODUCTION: 100
PERCH_DB_USERNAME: 4224dbe177fd
PERCH_DB_SERVER: localhost
PERCH_DB_DATABASE: venice-b
PERCH_DB_PREFIX: perch2_
PERCH_TZ: Europe/London
PERCH_EMAIL_FROM: shepherd.inbox@gmail.com
PERCH_EMAIL_FROM_NAME: David Shepherd
PERCH_LOGINPATH: /perch
PERCH_PATH: /srv/users/serverpilot/apps/experiencewalesinvenice/public/perch
PERCH_CORE: /srv/users/serverpilot/apps/experiencewalesinvenice/public/perch/core
PERCH_RESFILEPATH: /srv/users/serverpilot/apps/experiencewalesinvenice/public/perch/resources
PERCH_RESPATH: /perch/resources
PERCH_PRODUCTION_MODE: PERCH_PRODUCTION
PERCH_HTML5: 1
PERCH_DEBUG:
PERCH_RUNWAY:
PERCH_ERROR_MODE: DIE
PERCH_DATE_LONG: %d %B %Y
PERCH_DATE_SHORT: %d %b %Y
PERCH_TIME_SHORT: %H:%M
PERCH_TIME_LONG: %H:%M:%S
PERCH_PREVIEW_ARG: preview
PERCH_TEMPLATE_PATH: /srv/users/serverpilot/apps/experiencewalesinvenice/public/perch/templates
PERCH_DEFAULT_DOC: index.php
PERCH_DEFAULT_EXT: .php
PERCH_RWD:
PERCH_HTML_ENTITIES:
PERCH_SSL:
PERCH_STRIPSLASHES:
PERCH_PROGRESSIVE_FLUSH: 1
PERCH_AUTH_PLUGIN:
PERCH_DB_CHARSET: utf8
PERCH_DB_PORT:
PERCH_DB_SOCKET:
PERCH_APPS_EDITOR_PLUGIN: markitup
PERCH_APPS_EDITOR_MARKUP_LANGUAGE: textile
HOSTING SETTINGS

PHP: 5.6.8
Zend: 2.6.0
OS: Linux
SAPI: fpm-fcgi
Safe mode: not detected
MySQL client: mysqlnd 5.0.11-dev - 20120503 - $Id: 3c688b6bbc30d36af3ac34fdd4b7b5b787fe5555 $
MySQL server: 5.5.43-0ubuntu0.14.04.1-log
Extensions: Core, date, ereg, libxml, openssl, pcre, sqlite3, zlib, calendar, ctype, dom, fileinfo, filter, ftp, hash, iconv, json, SPL, PDO, bz2, posix, Reflection, session, SimpleXML, snmp, soap, sockets, standard, tokenizer, xml, xmlreader, xmlwriter, zip, mysqlnd, cgi-fcgi, bcmath, Phar, curl, mbstring, gd, gettext, imap, intl, exif, mcrypt, mysql, mysqli, odbc, pcntl, pdo_mysql, PDO_ODBC, pdo_sqlite, readline, shmop, tidy, xsl, Zend OPcache
GD: Yes
ImageMagick: No
PHP max upload size: 512M
PHP max form post size: 1M
PHP memory limit: 256M
Total max uploadable file size: 1M
Resource folder writeable: Yes
Session timeout: 24 minutes
Native JSON: Yes
Filter functions: Yes
Transliteration functions: Yes
TMP: /srv/users/serverpilot/tmp/experiencewalesinvenice
TEMP: /srv/users/serverpilot/tmp/experiencewalesinvenice
TMPDIR: /srv/users/serverpilot/tmp/experiencewalesinvenice
PATH: /sbin:/usr/sbin:/bin:/usr/bin
USER: serverpilot
HOME: /srv/users/serverpilot
FCGI_ROLE: RESPONDER
SCRIPT_URL: /perch/core/settings/diagnostics/
SCRIPT_URI: https://experiencewalesinvenice.org/perch/core/settings/diagnostics/
HTTP_HOST: experiencewalesinvenice.org
HTTP_X_FORWARDED_FOR: 92.2.36.220, 92.2.36.220
HTTP_CONNECTION: close
HTTP_ACCEPT_ENCODING: gzip
HTTP_CF_IPCOUNTRY: GB
HTTP_CF_RAY: 1f239dd7a4dc137d-LHR
HTTP_X_FORWARDED_PROTO: http
HTTP_CF_VISITOR: {"scheme":"http"}
HTTP_ACCEPT: text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,*/*;q=0.8
HTTP_USER_AGENT: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_3) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.65 Safari/537.36
HTTP_DNT: 1
HTTP_REFERER: https://experiencewalesinvenice.org/perch/core/settings/diagnostics/
HTTP_ACCEPT_LANGUAGE: en-GB,en;q=0.8,en-US;q=0.6,cy;q=0.4,nb;q=0.2
HTTP_COOKIE: __cfduid=d2998972cdb0955963cef01ced6e3aa151429977369; PHPSESSID=350323c7d32850febb45f1279a50844f; cmsa=1; _ga=GA1.2.796922246.1430949877; _gat=1
HTTP_CF_CONNECTING_IP: 92.2.36.220
LD_LIBRARY_PATH: /opt/sp/apache/lib
SERVER_SOFTWARE: Apache/2.4.12 (Unix) OpenSSL/1.0.1f
SERVER_NAME: experiencewalesinvenice.org
SERVER_ADDR: 127.0.0.1
SERVER_PORT: 80
REMOTE_ADDR: 92.2.36.220
DOCUMENT_ROOT: /srv/users/serverpilot/apps/experiencewalesinvenice/public
REQUEST_SCHEME: http
CONTEXT_DOCUMENT_ROOT: /srv/users/serverpilot/apps/experiencewalesinvenice/public
SERVER_ADMIN: webmaster@
SCRIPT_FILENAME: /srv/users/serverpilot/apps/experiencewalesinvenice/public/perch/core/settings/diagnostics/index.php
REMOTE_PORT: 34528
GATEWAY_INTERFACE: CGI/1.1
SERVER_PROTOCOL: HTTP/1.0
REQUEST_METHOD: GET
QUERY_STRING: extended
REQUEST_URI: /perch/core/settings/diagnostics/?extended
SCRIPT_NAME: /perch/core/settings/diagnostics/index.php
PHP_SELF: /perch/core/settings/diagnostics/index.php
REQUEST_TIME_FLOAT: 1433588458.1855
REQUEST_TIME: 1433588458
argc: 1

I appreciate it now needs an update to 2.8.7, which I'll do now.

Is there any way to recover the latest batch of missing images? I haven't backed up for a few days - tend to do it weekly. The invigilators are in Italy uploading these images from iPads through a slow internet connection, and I don't want to have to ask them to do it all again!

I know I can disable asset cleaning with define('PERCH_CLEAN_RESOURCES', false); but I think it's a useful feature and would like to keep it if possible.

Thanks for your help!